idler pulley & belt tensioners

[melmount]

I was thinking of replacing the serpantine belt and the idler pulley on my wifes truck. I figure good preventative maintenance. I pay attention to mine, if something broke or the fan belt was off i would know it. She would keep driving til it siezed.
Are the belt tensioners also something i should replace? seeing as it has 2 pulleys, plus the internal tension spring? It seems to be fine? But looking for input. I hear a lot on idler pulleys failing, how about the belt tensioners?
thx

[CEMotorsports]

Ive got a 97 ps with 215,000 and a 99 with 270,000 on it and I replaced the pullys just because they dont last forever and when the go out ur stuck. they were only like $20 ea. Thats a lot cheaper than a tow bill or worse.

[Broncoboy79]

Well my belt tensioner assembly completely fell of my motor about two weeks ago. So Id say go ahead and replace it for preventative maintenance. It was only like 70 bucks. Cant hurt