I have a Whirlpool machine and it has a lint filter which I clean maybe once a year. It's never all that bad...
I never had a problem with smell or gunk build-up. I never wipe the lip, but sometimes I might find a loose button there. But I always leave the door open between washes. The only thing I need to clean every month or so is the detergent dispenser drawer.
Oh, and I've had my machine for almost 5 years.
However, since Friday, it's been making funny sounds, so I'll be looking at the filter an hoses and hopefully pull out a sock and then the machine might be fine again... crossing my fingers.

Saša