I am 45 and do most of my own maintenance on my 60yr old small outboards, and also my 2009 Suzuki 90hp. With 12 years of use under its belt, I took the Suzuki in last fall and paid $725 for them to do a full winterization, impeller, plugs, etc. This spring I noticed that they didn't tighten the bottom screw in the lower unit so it leaked all over my neighbor's garage floor throughout the winter. It could be coincidence, but the motor died on it's third trip out this season. It ended up being a dead IAC valve.
I take it to the pros when I can't do it, but learned an expensive lesson about letting the "pros" handle routine maintenance. Oil, filters, impeller, and plugs would have cost me about $150 and I would have done it all correctly.