i got 10w30 Mobil synthethic, like,,, pfff.. 4000 miles, on a b20, i race like every 3 weeks, and take long trips of about 400 miles on the weekend... i check my oil all the time, level, viscosity, cleanlyness, and its fine.. its still pretty clean and clearish...
i also had a stock 94 ex vtec, i changed the oil at like 5k, and the condition of the oil was a bit more screwewd...
i liky synt, it last aaaa longer time... last time i changed it was like at 8k on my civic, and it was still good oil, my mechanic told me, synt is really good....
and my dad has a 91 accord with 280k same engine, and he uses some cheap 2 dollar valvoline oil, and his engine never had any problems... it still runs perfectly fine.. but his oil doesnt last as long as mine, when we change his oil, at 4k, its alot darker, and viscosity is shot...
i think, just be cautios about ur stuff... always check it, it take only a couple of seconds, plus, its nice to see ur engine... like a lil baby.. just sitting there... hehe...
one thing i do not recoment though, is switching back and forth on oils,
ive seen bad stuff happen with that...