is their any correlation between type of transmission , style of driving , etc that causes the chain tensioner to relax? or is is just poor quality part or design.

 

Normally chain tensioners don't relax, they either work or they don't. The tensioner is a spring loaded piston that works off oil pressure, the spring is only really even there for start-up, before oil pressure builds.
The only failures I know of are:
1. A ridge will eventually build up on the piston allowing it to catch and not extend proberly (most common)
or
2. The oil passage will get plugged or gummed up not allowing pressure to build inside the piston. (hardley ever happens, esp. w/ propper oil maintenance)