I just got done doing a head job (due to a broken timing belt) on a BMW 325i engine with 185,000 miles on it- it has the positive seal type seals from the factory. Even with that many miles on it and being over 15 years old the seals were still in good shape- the lips were a bit torn but the weren't leaking, but the guides weren't worn out of spec either. I'd put those seals on any head where you are in there already and care about the seals.

1950 Chevy pickup with '62 261, 4 speed.