Ok to just tighten a leaky valve cover gasket a little?

[TurnAround]

I own three M54 engines, but for some reason the X5's valve cover gasket like to go out. I've had three of them over its 117k life. My indi mechanic has done the work each time. Both replacements only seem to last 30k or so, and then oil leaks start to show up. Always past labor and parts warranty with them... ugghh.

So, back in the day. You know, the Triumph Spitfire, Chevy Nova, VW GTI days, we would just snug down the valve cover bolts a bit, between actual needed valve cover gasket changes, because, we all knew that the gasket would settle in some (shrink a bit) and need snugging down, and then all was fine... for a really long time.

So, what's the rule with these engines today? Ok to re-torque them to spec as a first step? Or, when my mechanic says its leaking, it will always mean a new gasket?

Any other pit falls to this I'm not seeing? (Like, its all linked in with CCV too, so don't mess with it).

THanks!