Going from memory here, the trigger return spring is the first to replace, around 7-8k trigger pulls. I have not kept a good record of dry fire and live fire over the past year with this P30, and I had a few of the springs around already. It wouldn't have been a big deal to shoot this one until it broke, since it's my dry fire and range trainer, but what the heck.
I changed out the firing pin block spring and firing pin spring, since I purchased the P30 used a while back and never checked them out. I believe the originals still had life in them since they weren't in pieces. I have seen firing pin springs break in half after about 5k rounds, but still function.
I didn't replace the recoil spring, since I don't think this P30 has anywhere near 25k through it, and that's about the replacement timing for that one.
I left the flat spring, hammer spring, and detent spring alone after inspection (I didn't have any spares on hand anyway), but also replaced the elbow spring and extractor springs.
Ultimately, I felt like dissecting it and cleaning it up early on a Saturday morning, but it's not something I will do again for a long while :)