New valves and seals....keepers?

What is the general consensus regarding using new valve stem keepers with a brand new valve after grind and fitting?
Obviously new stem/guide seals is a no brainer at this stage and costs,

It is good practice to install valve guides if the seats are to be ground. New valves should have new keepers. At that point, springs should also be replaced.
A good shop will not grind the seats without new guides.
Steve

Very good... getting my self prepared for the bad news with regards to that head I thought was rebuilt years ago...
I have nearly a complete set of NOS valves for these late 70's Z1 KZ900-KZ1000 heads but no keepers, guides, springs or seals. :S

Added: I am wondering, as suggested a few days back, if maybe I did pop the rebuilt head on this bike years ago and this worn one is my original head with only +25K miles on it.... maybe in my youth I was a little rough on it. LOL
... I'm gettin' old and just don't know. I've had too many project Yamahas, Hondas, Zs and KZs bikes over the last 40 years.

I've reused both springs and keepers many a time. Measure spring height and if they meet the spec, I wouldn't be afraid of running them assuming you are not going to be racing to redline all the time. On a stock bike the keepers should be fine too.

Cheap insurance. I replaced mine. Always wanted to and waited until I could.
Steve

No need to fit new keepers unless you need an excuse to waste money.

zed1015 wrote: No need to fit new keepers unless you need an excuse to waste money.

LOL... I've already done that on this machine over the last +37 years.