When do you know you need a valve job?

[Granite]

My 911 was supposed to have had one done a year ago, but there was no record of it when I bought it, just the owners word. Are there any tell signs of when you should do this?

Thanks,

[Por_sha911]

Are you talking about a valve adjustment or have the heads worked on?The most obvious sign of needing a valve adjustment is loud ticking. Needing a valve job (heads worked on) will be burning oil and poor performance.

[BoogieOnSkis]

If you're talking about a valve adjustment, I don't wait to hear the ticking, I adjust my intake and exhaust valves once a year. My car's a daily driver (approximately 10K miles annually).