how much do strings impact your sound? i have had the same strings for 2 years and i havent noticed anything. also, what is the purpose of different gauges?
first: Strings dont really affect your sound unless you just changed em. They give you twang until you wear em down. So yeah, they dont really change your sound that much.

2. the gauges are there because the higher the gauge the clear the notes and the better in tune the notes are in lower tunings. the higher gauge just helps the guitar mainly stay in tune for lower tunings (ex. Drop C, drop B, etc).
the smaller the number(ie .009 .011 etc) the thinner the strings they are therefore easier to play but some players prefer thicker as i believe they give heavier/warmer tones. not sure exactly but i think thats right. also you really ought to change your strings after 2 years
different gauge strings is mostley a prefrence... well in my opion. but im pretty shure heavy bottem slinkys are the heaviest strings ive used. sound wise. but i switched from those heavys to super slinkys and the sound was weak... the heavy bottems are the best setup ive played so far... caz the heavier the strings the harder it is to bend the bottem ones. its like pressin you good finger on the buisness end of a jack kife... it hurts... if i were you ide try the heavy bottems
Once you change your strings, even if you keep the exact brand and gauge, they will sound VERY metallic and bright, that wears off though.

Higher gauges handle stress better and are much harder to break, but do not sound as bright as lighter gauges, which are easier to bend and do not require as much work to fret and barre.

Hope that helps.
ive used the heavy bottems in normal tuning. they work fine... i think it goes 10-52. the low e string and the a and d strings in a bigger size are great for goin into drop c. but then again stairway to heaven sounds just peachy. so petty much you can go from bands like led zeppelin or iron maiden to system of a down or dethklok. black sabbath too if you play like tony and tune ur strings way down. ( i play most the black sabbath songs that way it just takes some improvation)
yea change ur strings more often too... they must be soooo dead by now. i change them every 2 or 3 months depending on how much i play sorry i think this will be my last post on this subject