To change or not to change.

[Barbel Mick]

I am having the valves checked on the 650 at the end of the month/early March.
This will be the third time that the cam cover will have been off, is it time to put a new gasket on? I don't know if it was changed first time, second time I know it wasn't. 
Would you normally change this gasket every time, or at least every other time, or definitely if it's the third time it's been out?   
Cheers.

[Rixington43]

I took Kwackboys advice and went on feel, does the rubber still feel supple and take/erase a finger nail mark.
Mine still seemed good and I very much assume they're original at 17years and 32K. A sparse application of Hylomar on the half moons and I've seen no evidence of leaks in the few hundred miles I've done since the service.
Obviously if you've any concern then they're not a mega cost and getting in to replace them is a faff but I wouldn't replace by default.