Whoever comes to your door is someone who works on garage doors full time, on the kind of hardware this area actually has. Housing in and around Naperville mostly went up between 1938 and 2003, with the bulk of it dating to the 1960s and '70s across the roughly 80 named subdivisions and areas in this part of DuPage and Will counties. That means a lot of original torsion setups, some side-mounted, some with hardware that hasn't been made in decades.
We don't send someone who's only ever touched newer belt-drive openers. The truck carries parts sized for older torsion springs and steel track from that era, along with current opener stock, because on any given day we might be swapping a 1970s spring assembly in the morning and installing a new opener in the afternoon.
One honest limit: if your door needs a part that's genuinely obsolete - some early aluminum panel systems from that period, for instance - we'll tell you when replacement makes more sense than chasing down a part that isn't stocked anywhere anymore. We'd rather say that up front than have you wait weeks for a part we can't guarantee.