Oven trouble

I'm wondering if anyone out there is having an experience like mine. My oven keeps shaking itself apart. For the second time (1 last year, 1 last week) we have arrived home to find problems with our oven. This time the stovetop had popped off, last year the glass door fell off (but did not break). Upon inspection both times, I'm finding that just about every screw that holds the oven and stove top together has come loose and fallen out. Last year the fix was easy as all I did was re-install the screws and tighten them up. This years problems has been a little tougher. A screw that holds the bottom plate inside the oven (that covers the pilot assembly) fell out. It is mounted using a nut and washer on the inside of the oven screwing onto a screw that passes through the oven wall. As far as I can tell the only way to get this screw back in place is to disassemble the entire oven, which I do not want to do. ( I have gone as far as I can without disconnecting the propane lines) I have fixed it for the time being by using a sheet metal screw and connecting the plate to the side wall.
Do any of you have similar experiences? Does this happen on a regular basis? I guess I need to make screw tightening a routine part of getting ready. Thanks for any replies