Security is always an important aspect. Theft is still a prevalent issue in Hellmoo, you never know when a crafty outlaw or asshole you challenged might pop up and whatnot. It is currently against the rules to rob a player's home or steal their vehicles if they have been online in the last 60 days, or you have challenged them.
Why was I robbed?
Simple reason: you were logged out for more than 60 days or you had a challenge against another player or corp Other than that it would be advisable to invest in a decent lock, an apartment in a good neighborhood and to not get in any fights you aren't prepared to finish. Rent in Freedom City if possible, install a good lock, and log in now and again.
Who can pick?
There are a pair of skills in this game, Locksmith and Hack. The primary use for these two skills are to pick locks. Locksmith picks physical locks (the type you need keys to open), while Hack picks biometric locks (the ones you open with a hand-print), although if your Locksmith skill sucks it makes picking biometric locks harder as well. They interlink in this way. Mainly builds centered around brains or reflex make good lock-pickers, typically whippers. It is also used in some quests and in the crafting.
What lock should I use?
.There are quite a few different locks in the game, and they differ in what levels of security they provide.
Scanlocks: Scanlocks are picked open by anyone with a modicum of skill rather easily. Your apartment probably came with one of these, its only to stop uninvited guests.
Voxguard bronze-platinum: For players buying voxguards is the easiest, bronze to gold is sold readily by NPCs in Smoot's Security Shack and Securite Entiere. These offer decent protection, but wouldn't deter anyone who has actually invested time into lock-picking.
Voxguard Diamonds: Very hard to break through, requiring around 30 total hack and locksmith. Craft-only, and a bitch to craft at that, as far as protection goes this is as good as it gets.
Lets face it, your home is a place for your stuff (ever notice that your shit is stuff and other peoples stuff is shit?), and if somebody breaks in, chances are they aren't going to take that shit you were saving. They are going to take the good stuff, the SHINY stuff, the VALUABLE stuff, not that shit you were saving. That's why you gotta lock up your stuff!
Also, if you share your apartment with another person, you can keep your things separate by individually locking your own containers. Which of course means nothing if your roomie lets any pickers in, but oh well.
Locks: Changing the door lock is of course important, many people also put locks on the doors insides to stop people from leaving to quickly as well. Voxguards, as mentioned, are preferable.
Peepholes: A peephole is an extremely valuable, common, and cheap tool. It allows you to peek out your door without opening it, to see if something dangerous is outside your door. They are installed on the OUTSIDE of the door.(This is the biggest mistake people make, placing them on the inside allows people to look in and watch you sexhabe). They can be had for a low price at Smoot's Security Shack.
Door Kits: Door kits are an extra step in security. Informer door kits do what the name implies, inform you through your wristpad's radio if someone is trying to pick your lock. This isn't that important since when someone starts picking your shit it issues a challenge, but is nice for knowing exactly where if you own more than one apartment. Another viable and easy to obtain option is a TrickrTreat kit. These fun little kits are single use explosives that go off when somebody picks your door and fails a roll, for best effect place several remote mines outside the door, when the TrickrTreat explodes so do the mines. You should also grab a shockmaster to put on. The shockmaster is like a trick-or-treat, but with electric damage and unlimited uses. They're craft only, but can easily cause most pickers to fumble their picks with some reliability. Beware that this means nothing to the greatest pickers. The only way to get a shockmaster is from a player crafter.
Homecams: A homecam is a last resort item. It wont do a damn thing to protect your stuff, but it will let you know who did and exactly what they took. Not useful beyond knowing who to get your revenge on, but if you want to have absolutely everything, get one, they are cheap. They can replay a short log of the most recent actions in your home.
Stickycams: A stickycam is a great way of showing exactly what the robber is doing, allowing you to (hopefully) assemble your stronger corpmates into a ganksquad or to just go beat his ass yourself.
Tinfoil: Tinfoil can be installed on your walls and gives a large chill penalty but prevents people from using clairvoyance to peek into your apartment or vehicle. This can backfire though, giving people the idea that you do have good stuff on the inside or that you're doing something naughty. Only needs to be installed in the rooms from where you can exit or enter.
Securing Your Items
What any robbery comes down to is that the picker is after your things. The most important thing you can do, is make those things harder to pick out, or harder to get to.
Stashing: The poor mans safe. You can stash an item in a room to have it require a search to find it. In an extended robbery, this is even better than a safe, since if the picker doesn't think to search, the item will not be found. The downside is the item is stashed at your current scavenge level. If someone with much higher scavenge than you comes in (ie the robber) they'll get a message telling them that something is there.
Containers: Locks can be placed on containers as well. Hiding your good stuff in an unlikely locked container is a good idea to foil robberies, if you would be inclined to do such. This of course means nothing to players with Xray Vision.
Corp HQ: Storing things in your corp HQ might be a good idea as well, though you run the risk of losing it if the corp dissolves or you piss off another player in the corp. Corp HQs are very safe, but you have to factor in that a dozen other players might have access to it.
Safe Deposit: Famous Original Ray's Safe Deposit is located in Freedom City. If you have a valuable item that you aren't going to be using, and you don't want it lost in your sea of texty storage, it goes here. You get 10 slots to store items (no bags) for a slight fee based on the value of the item. It costs nothing to remove the item. There is no way an item can be stolen or lost from the safe deposit.
There are several different locations you can rent an apartment in Hellmoo, and if you have the funds, you can even buy your own custom house. I'll go down the list describing the pros and cons of each place.
Broham Gardens: This is the cheapest apartment available. That's all the good I can say about it. The security is practically non-existant, compromising of Gorillabots that most can kill with one hand tied behind their back. It wouldn't be advisable to be living here permanently.
Astral Complex: Similar to Broham, however, security also includes two Owlmen, who are actually pretty tough. The monthly cost is also cheaper, though the downpayment is more expensive.
The Bradbury: The Bradbury is a decent apartment all around. Its got a relatively decent security force. It is cheap and has a shitload of rooms available.
Sweaty Palms: Sweaty Palms is also a good choice, if you can get a room. It has electrified floors and FCPD cams, however it is pretty far from the police HQ, so don't expect to be saved by McBain.
Helliday Inn: Very hard for a solo player to even attempt to rob, as it has electrified floors (cement shoes) and lies very close to the police HQ. It's a very popular place for players due to the illusion of grandeur, meaning a lot of decently wealthy people to rob.
Halliburton Arms: Halliburton Arms is located in Burbclave, and is significantly more expensive than Helliday (500k to move in). The security here consists of swarms of robotic spiderlings, which use curare darts and can easily paralyze any would-be picker unless they have high endurance (being a picker they probably don't). A step up from Helliday in terms of luxury, but the price is generally enough to keep most people from owning one.
Burbclave Mansion: Burbclave mansions are of course the top of the line. Several rooms, an unsoakable orbital defense cannon that blasts away anything trying to break in and your own re-cloning facilities.
Lurleen: Lurleen's security is literally non-existent. The only advantage to living here is obscurity, which isn't going to stop any pickers you've challenged.
The Rodger Young: Pirate ship in botany bay, with security consisting of several well-armed pirates. The major disadvantage to living here is you can't install roomkits (you're on a fucking boat).
Vault 4: Vault 4 is guarded by very aggressive turrets. The turrets serve to safeguard the residents, so don't wander around too much if you don't know the layout of the Vault. Of course, the turrets aren't going to stop any determined picker, and you won't have any backup from FC law enforcement.
Necropolis: Hideous Freak and abomination housing only. Security consists of several abominations, so chances are you aren't going to be robbed unless the person you challenged really fucking hates you.
Custom Housing: Custom Housing nowadays is very secure as most players include security systems in their plans. Be very wary of breaking into anything like this.
Vehicles: Any vehicle left unlocked can be stolen, and such is NOT against the rules today. If you want to protect your property put a lock on it. Stickycams can be used with airplanes to get a view over who moves around (but useful for spotting friends in the area and NPCs you are looking for).