Is it worth it to replace head gasket- still running 275k miles

[Sagaris]

It is not uncommon to hear of 300k mile bottom ends. There is of course the million mile E30 that Mobil 1 strapped to a dyno and ran non-stop, but that isn't quite real-life conditions. Someone had mentioned that they spoke with one of the engineers that helped design the M20 and it was designed for 500,000 km or 3xx,xxx miles, I am too lazy to do the conversion. If that is true, then that is pretty cool.

[ridefastakechances]

Mine has 300k+ (odometer was broken for a while) and runs like a champ! Head was rebuilt about 170K.