Whenever it's time to start doing maintenance on your planter, here's a tip related to lubricating trash whippers, row cleaners, or whatever you call those tined wheels that clear last year's crop debris from in front of the planter's disk openers.
Most of those tined wheels have grease zerks on their hubs, which implies they need some sort of regular lubrication. Maybe, maybe not. I can't speak for all manufacturers, but in many brands of tined row cleaners, the factory-installed bearings are sealed bearings. If you check printed instructions that come with the row cleaners for assembly and installation, or go online and find those instructions, there is a paragraph that says if the user wants to grease those bearings, the seal must be removed from one side of each tined wheel's hub bearing.
Greasing a tined wheel hub bearing that hasn't had the seal removed is at a minimum a waste of grease and time. At worst, grease is packed so tightly into the hub that it presses the seal INTO the bearing where it rubs against the bearing's balls and potentially reduces their longevity.
The only way to tell if the bearings in the hubs of your tined row cleaner wheels are "greaseable" is to disassemble one, clean out all the old grease, and study the situation. If the bearing has seals on both sides, greasing has no benefit. If the seal is gone from one side of the bearing and you can see the little balls on that side, it would be good to grease all those tined wheel hubs regularly.
If the bearing's seals are intact and you prefer to have greaseable bearings, you can use a small screwdriver to remove the seal on the side of the bearing toward the grease channel/void. That allows grease pumped into the hub's zerk to get into the bearing. Just be sure to add "greasing row cleaner hubs" to your regular maintenance schedule.
I've seen no difference in the lifespan of greaseable bearings versus sealed bearings on planter row cleaner wheels. As long as the seals are intact, sealed bearings last as long as bearings that have had the seals removed--as long as those "unsealed" bearings are regularly greased.
And, in answer to the question that's always asked when I point out the sealed/unsealed option to customers---I don't know why manufacturers put grease zerks on wheel hubs then install sealed bearings.