the only time I'd be concerned about this is mixing grease bases that aren't compatible, you can look for a chart online that tells you which grease bases shouldn't be mixed. I try to start with one and stick with it so it doesn't become an issue. I use Lucas Marine (blue grease) for trailer wheel bearings, the gimble bearing on the I/O and I use Evinrude Triple Guard on the splines on the driveshaft because it seems to hold up the best of all the greases I've used. I use it on the prop shaft as well and on the shift linkage, and other sliding surfaces. Even after the boat is in the water all season when I pull the prop at the end the Triple Guard is still on the prop shaft! Very water proof.