Why replace tensioners when replacing guides?

[tmorgan4]

After reading all of the write-ups on this site about replacing the bad (plastic) timing chain guides, I'm still puzzled as to why all of the parts lists include all the tensioners on the engine. I know that the parts lists are VERY complete, but are these really necessary? These tensioners aren't the problem, it's the guides. I've got one brand new tensioner (13070-60U12) but I'd need to order the other 5 or so if I were to replace them at $50 apiece. I noticed the list includes timing chains as well which "Should last the life of the car."

Replace or not replace? All but one are used but appear to be in great shape and still move freely.

[Q45tech]

The tiny oil orifice that pumps them up can gets restricted/varnished up and the spring loses tension over the years considering the damage a failed par can cause total replacement is cheap.

The same reason the oil chain and oil tensioner/guide are replaced.

Anytime the labor [at retail] exceeds the parts cost you always replace as much as you physically can.

The part you don't change always fails FIRST.