Don't bother with string conditioner. Just change them.
I would oil the fretboard when you have the strings off too. Gibson makes a good fretboard oil. I wouldn't use anything on a guitar that isn't made specifically for guitars.
I don't clean them after 15-30 minutes of playing unless they need it but I HATE touching a guitar(ie. demo at guitar center) only to feel the doodoo and chocolate all over the strings.
When you're dropping just one string, you'll find that it puts extra tension on the rest of the strings and affecting their tune. you can either re-tune them and deal with the slightly affected action difference, or loosen the spring tension to account for the reduced tension of the dropped tuning. Actually, you'll probably do a little of both.
I know, there is all kinds of cool things I did not expose myself to when I was playing electric guitar more, which was years and years ago, because of some odd or weird (a.k.a. ignorant) notions I had in my youth. And I never really got to play much with anyone else who was really good. I would just sit and play in my room, trying to figure things out on my own, refusing to use books that would have helped, completely lacking the natural aptitude to have figured much out on my own. lolDADGAD is a great tuning. Very drony, and lots of fun.
So don't clean your strings after playing? Whew, not me... I could never play my guitar for a few hours(practice or a show) without using some kind of string cleaning.
I don't clean them after 15-30 minutes of playing unless they need it but I HATE touching a guitar(ie. demo at guitar center) only to feel the doodoo and chocolate all over the strings.
I have a few expensive guitars and I've never oiled them once. When I change my strings, I use some lemon or orange Pledge to wipe the fretboard down and that is it.
As far as tuning with a Floyd Rose, I adjust the springs every time, as well as move the fine tuners back into the middle position. I actually dislike the Floyd Rose, but I'm not a whammy bar kinda guy.
As far as string rusting goes just use Elixirs. I love them
I have an acoustic guitar I bought maybe 10 years ago. Never oiled it once, never changed the strings. Changed the strings about 2 weeks ago and oiled the fretboard. It needed it. Plays better now and the fretboard looks better than it did.
I have my Dad's Gibson SG, he has owned this guitar since the 1980s (it is a 1978 IIRC) but it hasn't been played in probably 10 years (my Dad passed away 5 years ago and he was suffering from medical issues for a few years prior to his passing). Anyway, the guitar needed strings badly and it also needed a good cleaning. One of the pickups had some build up on it but once I cleaned it and changed the strings it plays soo sweet now. Really a nice sounding guitar.
I have a '95 Fender Jag-Stang my Dad owned too. It is a left-handed guitar and it is in mint condition. I figured my son could play it. Guitar had the original strings on it and they wouldn't hold a tune for very long and they were really quite old. I put new strings on it and oiled the fretboard and it sounds much better (I can't play it though... damned lefties).
I would recommend oiling the fretboard when changing strings, especially if you live in a dry climate like I do. Use something made specifically for guitars though.