Magnitus: I don't know about the "top" or "mid" tier, but my logitech mouse at the "bottom" tier (I'm guessing by price here) is highly dependable... it is a mouse that does reliably what a mouse is supposed to do and doesn't break down... I'm not sure what else I should be expecting here. The basic mouse design suits me and it certainly won't brew my coffee for me.
Braggadar: Usually the M100s I used to buy died within 12 months. It's possible I have a harder grip than you do, so I put much more force into my clicks. In the end I found them too awkward to hold and needed a more ergonomic grip... and I enjoy mice with variable DPI settings. I also like a slightly heavier mouse so my movements are smoother and overshoot a bit less.
But if you've had a M100 that's lasted more than a year without falling apart or having the micoswitches go bad I'd say you're lucky.
EDIT: I've also had a M105's LED fail. The sensor still worked, but not the light. So it's not all about the microswitches ... the mice are cheap for a reason.
Thanks for the input. That would certainly explain a lot.
Honestly, I don't exert a significant portion of my strength when clicking the mouse on a regular basis (maybe the occasional bout of frustration, but it is very uncommon and even then, I don't click with all my strength), though if I did, I (and probably most adults I would gather) might need much sturdier equipment (I certainly haven't troubleshooted my computer mice in this way).
For the awkwardness to hold, I guess that's a personal factor. The mouse is certainly a lot smaller than my hand so I only use the upper left part of my hand (my index and my middle finger are resting on both buttons, my thumb is on the left of the mouse and my two other digits are on the right, the mouse occupies ~50% of my palm's width and maybe ~33% of its height). Most of the hand is not engaged, but I'm kind of used to it. Maybe if it was a completely new experience, I'd want something to occupies my entire hand, I'm not sure. I don't think of it much honestly, it is very reflexive at this point.