In a Chevy 2.2 liter engine there is no timing belt tensioner because the engine uses a timing chain. A timing chain tensioner is a big job. If the chain tensioner is wearing out in 3 months there's something wrong and you need to find a mechanic who can put one correctly or find the cause of the failures.
I don't think you are talking about a 'timing tensioner' but rather a drive belt tensioner. That shouldn't be going bad very often either. There's a parts problem, a tensioner alignment problem or a mechanic problem.
If you are eating up drive belts, then something is misrouted, the belt is rubbing on something, or there's a driven component (like the alternator), that's siezing up and burning up the belt. With the belt off, check to see that all the driven parts are rotating freely.
It's not easy to get a serpentine belt on right the first few times you do it. I remember my first experiences.