ZX9R B 20k service

[timeeh]

Well ol girl just hit 20k and I having a look through the service manual it tells me it's time to check the valves. Just wondering what everyones thoughts are on this, as after a bit of reading through old posts, it looks as if everyone waits till a bit fruther down the track, so i thought i'd see what the "general" consensus was. Also what other things should i look at other than
Oil + filter
Clean air filter (new one install 4k ago)

anything else you guys can think of let me know. Also plugs and coolant were also changed 4k ago.