Pickups can have a significant impact on tone, and changing pickups will be a good idea if: (1) you know how you want to change your sound; (2) that change is possible by changing your pickup (e.g., you won't be able to make a Jazz sound like a Sterling); (3) you look into which pickups might help you reach that goal; and (4) you like the bass enough otherwise for the mod to be worthwhile. You shouldn't assume that an aftermarket pickup will be an upgrade; it might change your sound, but you might not like the change. You might also be able to reach you tonal goals more simply, with different technique, different EQ settings on your amp, or different strings. Experimenting with different pickups is fun, but it can also be expensive and distract you from trying to improve as a player.