It depends on how much I'm using the machines, how much roading I do and how many round bales I'm moving and loading on customer's trailers. Last year it required no adjustment.
I still, however, loosen the jam nut and tighten the through bolt and then back it off 1/4 turn. My shop manual calls out a specific starting effort (torque) for the front axle assembly that I've never ckecked, I just use the 1/4 turn method. I suspect if it was too tight, the brease could not escape and nine does, All the fixing bolt does is bear on the inner pivot assembly, I've removed it before to see what it does and that is what it does.
I have no idea if other units use the same 'slop removal' method, but mine do. LIke I said, that may be unique to Kubota, have no clue about it actually.