The internal parts of the engine are not the weakest link in the chain for that year chevy.
There's no way to accurately predict "how long" or "how many miles".
If it's not using any oil, or very little, between oil changes I wouldn't worry about it or bother
paying for a compression test.
Last Nov I replaced the speakers* in my 98 chevy. It sounds better than it ever did and it should help to make my truck last a long, long time.
*JBL 608c's from Amazon ... if you're sticking with the stock HU and want a cheap upgrade.
