The "Conditions" may have originated around the time of the 1911 design, but they do not apply just to that type of weapon.
Condition 1 - Round loaded in the chamber, the weapon is cocked or primed and ready to fire, but it has a safety in place to keep it from going off on it's own. Ideally this should be a manual safety that the user has to intentionally switch off.
Condition 2 - Round is loaded in the chamber, hammer is down and safety is off. To fire one must pull back the hammer like you would see a cowboy do when he pulls and fires. Striker fired weapons have a mixed bag of people saying you can/should and you cannot/should not carry them in condition 2. I don't like striker fired weapons, so I don't own one. I never carry in anything OTHER than condition one, because it's the way JMB intended me to carry.
Condition 3 - No round in place, magazine is in place, any safety is off. You have to pull, rack the slide to chamber the round, then shoot. I believe it is the Israeli's that have perfected this to prevent against accidental/negligent discharges and they are VERY effective at it. They also teach an advanced way of point shooting that aids in their accuracy, so it's difficult to say if this version would be viable or advisable to someone that wasn't trained in their method of doing things.
Condition 4 - The never talked about, bastard cousin of Condition 3 that I personally think was invented by someone with too much time on their hands and an honest attempt to please both the people who want to get the weapon in play fast, but also NEVER want to worry about an AD/ND. In Condition 4, your weapon is loaded with a full magazine, but the weapon is cocked, hammer/striker is all the way back and the safety is off. When you draw, it takes MUCH less pressure to re-rack the slide and chamber the first round, thus you have a blend of Condition 3 and Condition 2. If you ever finger the trigger, there is no round in the chamber to go off, but you don't need the extra strength and positive grip to exert the full ( est. 16 pounds ) of force to rack the slide in that moment of life or death.
Consider the safety devices of YOUR
weapon and decide what YOU
are comfortable and feel safe doing. Don't rely on us to tell you what is going to work for you, it might not.
I prefer Condition One and only Condition One, because if the time comes, my goal is to go from "Yo Homie, is that my briefcase?" to SMOKING is an instant.