Has anyone noticed tone improvements by swapping out switches and pots?

[orpheo]

You can just measure the pot to verify.

'you can just'.
No.

When you have to scrounge through literally thousands of pots per shipment and you want to have consistency, measuring every single pot is just not an option.

[LesStrat]

Yes, when changing pot values.

[IMENATOR]

Not really. Switching to different pickups is the most important change but upgrading pots/switches is a good idea if you think the stock ones could fail at you at some point. The second most dramatic tone improvement ever got was turning my close back cab into an open back (I simply removed the back cover), it was like removing a blanket from the speaker. I always had this narrow view of "open back for vintage, closed back for high gain", I enjoy my high gain sound much better now.