Ive had aset of Lucky bearings, some Abec 5s, for ages now. I dont use them for my regular setup anymore ,just for the cruiser, but I skated them heavily for around 2-3 years, never did anything with them, maybe just some cleaning every 4 months, but never used any oil or anything ,and those fuckers are still going strong , after probably 4-5 years of heavy using.