Autosave has been very reliable and saved my work many times but today I noticed that all autosaves are gone. All I have is quit.blend and copybuffer.blend. I haven't changed my settings.
I cheeked this question and everything seems to be setup correctly. Autosave don’t work in 2.8
The only major thing I can think of is an Windows Update from yesterday. After working some more with Blender today, it seems that autosaves are generated but then they disappear. So maybe it has something to do with Windows rather than Blender itself.
My system Windows 10 x64 bit Blender 2.82a