If you are talking about blade spindles, and you use the mower commercially, two or three pumps from a grease gun is *not* enough. Each blade spindle on a commercial mower has an "overflow" hole. Each mowing day (I might do 5-10 lawns in one day) I grease the spindles until the grease starts to ooze out the overflow hole. I use a DeWalt electric grease gun and it usually pumps 20-25 times before oozing starts. Other pivot points require a lot less, and there are no grease seals that blow out on blade spindles, or anywhere else on a commercial mower.
Oh, and I never had to replace a blade spindle on my John Deere mower, going on seven years of commercial use. I did have to replace one on my Ferris walkbehind.