When I go over clingy mud, it builds up on the front wheel by the brake, and I have to dig it out now and then. On the back wheel, it builds up in two places - by the brake, and under the rear carrier.
I have to have a rear carrier, because that supports the batteries. But I had a look at it, and I decided that the problem partly is that it's too narrow. So I swapped it for a wider one, now there's a lot more clearance between the struts supporting the carrier and the rear wheel, so the bulidup of mud will, I hope, be less of a problem. Or to put it another way, a lot more mud will have to build up before the wheel jams.
I also re-taped the bike control switch, the tape had come a bit loose.
Finally, the cunning electrical connector that connects three batteries in series, passes the current through a 30 amp fuse and a breaker switch, while doing the clever spark-suppression when I connect - one of the wires had got a bit frayed, and it looked like some of the strands had broken. So I fixed that - it's not a big thing, but I'd not want it to come apart when I'm miles from the car. Although I do have a backup :-)
I oiled the chain. I see so many bikes with rusty chains, it makes me feel like walking around with a mask and oilcan and being the Phantom Oiler.
And I changed the container that I put the batteries in - that's to give them a bit of protection in case I fall off the bike, as happens now and then. The batteries I'm using now are slightly wider, so I'm using my ammo can style lunch tin.