I as well, do my own oil changes {and much much more}. Tired of bieng ripped off! {doesn`t do your engine any good either}.
Once a year I do the "Flush" thing On the crankcase. Here`s what I do, drain the old oil. leave the old filter in place. Add three quarts of #1 Diesel fuel and a quart of new oil. start the engine DO NOT REV IT UP during this process! Let it idle for four or five minutes. Drain all contents from the crankcase, remove the old filter. Replace with your favorite oil and a new filter and be on your way. I know some of you will shudder at the thought of doing this. I`v been doing it for years on various vehicles and have yet to cause any harm to one. I have a 98 Honda Accord going on 275,000 miles now and it runs like a top. My 1990 chev 350 Blazer is going on 250,000 {Gives a puff of Valve guide smoke} on start up but still running strong.
Whatever you do NEVER EVER send your wife to an oil change establishment or a mechanic They "See em comin`" a mile away.