1. Depending on personal preference, money, etc. people typically change strings anywhere from every day to every six months.
1.1. Find out what gauge the strings you have now are and buy several packs of different brands and try them out. Slinkys, Elixers, and D'Addario EXLs are all popular. If you want to try other gauges, you'll need to have your guitar setup adjusted.
2. For your style, I'd recommend a Jet City JCA2112 (combo) or JCA20H (head). They're low cost and suitable for classic rock and blues. Might be a little crunchy if you have to crank the volume all the way, though, and it's Class A/B rather than Class A. I'd say try out a bunch of amps and see what suits you.
2.2. Separate heads and cabinets allow you to mix and match and are easier to load up and haul to gigs. They also seem to be something of an ego boost for many people.
3. I find thin, flexible picks easier for strumming, but it's harder to pick with consistent force. Thicker, stiffer picks tend to make it easier to pick single notes. Pointy picks (e.g., Dunlop Jazz III) are often prefered for pinch harmonics, tremolo picking, etc. Picks are (with a few exceptions) very cheap, so buy a lot of different kinds and try them out.
I change strings when I break one. I have guitars with strings that are over 10 years old. Granted most of my often played guitar, don't have strings much older than a year. Just don't fall for thicker strings are better, get thin strings to learn on.
The simulating solid state amps are good advice. The Roland Cube amps are surprisingly good.
Picks is picks. I use Dunlop Tortex .88mm (I think), whatever the green ones are.
On another note, anyone have any experience with travel guitars? I get to spend a year in Central Asia coming up, and for obvious reasons not really planning to bring the Gibson. But I'd like to bring something small to stay in practice using headphones and AmpliTube.
I don't know about proper travel guitars (never seen one) but I do have a couple of YouRock's (www.yourockguitar.com) that make very interesting travel companions.
I bought 2 practice amps for my girls (Told the guy I wanted cheap but good) and the first amp he got me was a Roland 15w, has 4 presets, nice but just for practice.
The 2nd amp I bought he sold me for 100$ bucks, it is the Fender Mustang I, again a nice little practice amp, told him thank you, bought it and left. When I got home I thought I'd look up the Fender amp on Youtube and I was like HOLY SH!!T1!!!! If/when I get good enough to fill in for some local yocal band, I'm gonna get the Mustang III. The Mustang I can do almost every pedal you can imagine and is full of fun addons. Now this is just my opinion but did I ever luck out on this discovery.
Check out their promo, could just be fluff but I'm having a ball with this one: http://www.youtube.com/watch?v=BmDc9oKa_tg
Fair do's, Unfortunately my strat clone comes under the heading of "very poor quality instrument". I've never owned a Gibson Still anyone reading this thread should bare in mind if they change string guage they may need to adjust the intonation.
Wrong, you should not need to touch intonation with string replacement, if you are, you are tinkering too much or own a very poorly made guitar period and should buy a quality instrument and not even compare those crap guitars to quality instruments because they are nothing but firewood.