[Hib Halverson]

My belief is that smoke on start up, if it's very noticeable and happens regularly, is not normal, even for a '90.

While it is true that all the engines built prior to MY91 lacked exhaust valve stem seals and that contributes to higher oil consumption than with the 91-95 engines which had exhaust valve seals–and that oil use is constant, somewhat more than engines with "unsealed" exhaust guides–but they are unlikely to "smoke bad," unless there is some guide wear or some other mechanical problem.

Sometimes smoke on start up can be due to leaking injectors.

Also, smoke on start up could be coolant smoke and indicative of a head cracked around an exhaust port.

It depends on the type of smoke, white, blue or brown/black, and what it smells like

In any event, with 52,000-mi on the odometer and regular smoke on start up, you're looking at eventual repair cost.