Robert M. Gary wrote:
I'm curious how important it really is to punch in 1200 as soon as the
controller instructs squawk 1200 as you approach for landing at an
uncontrolled field.

Just one opinion: I was taught Aviate, Navigate, Communicate (in that
order). Transponder is just a communication, if I felt (as pilot in
command) that squawking VFR while entering the pattern to land would
reduce safety, then I wouldn't do it. I think it'd be important to
switch it before flying again, but I doubt a controller would be that
agitated if you kept it for a minute longer.

I'm also curious to hear what a controller has to say about this.

Ben Hallert
PP-ASEL