pickup question

It's almost always an upgrade or change of "sound". In general, pickups don't die, unless there is some mechanical breakdown, such as the winding breaking, but that's a rarity. You may (also extremely unlikely) experience the coating on the copper windings disintegrating and shorting (which would just cause a loss of performance, because less windings are actually having an effect).

I agree. it is usually an upgrade.

pickups rarely fail.
I have a few lap steels . one is from 1939. it still works great.
the 1940 lap steel had weak output. I found out the pickup was open..meaning there was a break in the wire winding.
I felt it important to keep the original p.u. so I had it rewound. it's great now and will last many many years.

having p.u.s rewound or altered is interesting. alot of those folks who build and repair p.u.s can over wind or underwind or scatter wind depending on what kind of tonal output you want.

Pickup replacements as "upgrades" are way overdone, often by people who don't know why they "need" to upgrade them. I'll skip the long dissertations I've written about why they're rather simple electromagnetic devices with only a few variables, none of which are "mojo" or "magic," and simply say this: You should play with the pickups you have until you're very familiar with how they sound. IF you can name specific characteristics of the ones you have that you would like to change, then and only then can you intelligently select replacements. Recommendations on guitar fora like "Dude, D'Expensivo Super Extortions are DA BOMB!" are quite useless.

Pickups aren't even the most tonally important part of the signal chain (that'd be your amp), and lots of other things can be changed to make big differences in tone without changing pickups. Like tone capacitors, for instance. And properly adjusting pickup height is very important with any pickup.

If you're going to play with lots of distortion, use any pickups. You'll never hear the difference. Humbuckers, P-90s, single coils... Pickups are subtly different, like a singer using different microphones, and you're going to hear that best when playing clean.

Guitar manufacturers aren't stupid. They don't put out guitars with "crappy pickups." But you may have particular preferences that would be better suited by different pickups. Unless you know what they are, though, leave those pickups alone. That's my advice.