mine is a fucking disgrace, which is odd cos I'm a super-clean clean freak and also clean ovens as a side-line.
have been in this house for over a year now and I've never cleaned the oven. it was bloody disgusting when I moved in, but deided this doesn't really matter.
it's started smoking recently when I switch it on due to all the crap welded on, but I still ain't EVER gonna clean it. it almost adds character, I say.
the top is nicely clean, though. give it a wipe every couple days.