I am not proposing that you ignore valve adjustment, but I just wanted to throw something in here.

My 240D original engine went 380,000 reliable miles on maybe four valve adjustments. The engine had ridiculously thorough oil changes, but few valve adjustments. It purred and always started the whole way.

This is one of those things that I offer with embarrassment, but that was my experience. When driving that car, I was driving a lot and buisier than a one armed paper hanger with an itch, so the valves just didn't get the attention that they deserved.

Have a great day,