Here are a few:foreverawhilemany yearseternityeverlasting
Yesteryear, maybe?
instead of long period of time, you can use phrases like:a long terma long spella phaseyou can even use the word tenure if it suits the situation.
thou is the really oldern time way of saying the word you.but i am not sure if that is the correct spelling.
Dwelt- to get a hold of something for a long time. or you have hanged around that thing for a long period of time Don't now the other word for dwelt(sorry!)
another word for no time to play is buisy
Analyze, monitor, keep track of
If Time : Duration If distance: Size/Length/Height as applicable.
Truly
REALLY long
no other word really...
sheep. Thats short.