Soldering smallest SMD components such as 0402 with Microscope?
Soldering 0402's by hand without using magnification is possible, but inspection is difficult.    Also, it depends on how old you are.  When I was younger I could do a lot of things without magnification, but less so now.

I can also solder all QFP, TQFP, SOIC, TSSOP's, etc by hand, but magnification is a huge help with those too.

But, not every microscope is appropriate for soldering!  You want a scope that has a large working distance.  Ideally about 6 inches from the lens to whatever you are soldering.  This gives you room for tweezers, soldering irons, flux bottles, etc.  It is possible to do with less working distance, but if you are buying a microscope anyway you might as well get one that is going to work well.

I cannot imagine a reasonable electronics lab today that does not have a microscope.