should i replace belts...A/C,etc Options

[captb]

just wondering if its time that i should replace the timing belt, or other belts now. car has 115,00 miles on it and not sure if it has been replaced in the past. car is running fine as far as i can tell but every once in a while it feels like its lacking in power at 1st gear when i start it and when i turn on the a/c it feels like its lacking as well. not really concerned with these to much cuz (1)engine is still cool=more friction and (2) a/c adds additional stress. but my main concern is the a/c belt is loud. i dont notice it so much cuz car came with an intake but my mechanic uncle told me its pretty loud. i wanted to replace all the belts at the same time; the skinny a/c belt, the belt to the alternator, and the timing belt at the same time without the waterpump. so just wondering....

1) is it hard to replace these belts? (they just slip off and on but im more concerned about proper tensioning)
2) should i replace all the belts, or just leave the timing belt when i have too?
3) or should i just add more tension to the a/c belt for a quick fix?

[Bitter]

might as well replace all the belts at once since they have to come off to do the timing belt.