Taking off the hitch every winter, will it damage the bolt hole?

It should not if you are properly torquing it down. I would use blue loctite, it will prevent corrosion and keeps bolts from backing out.

 

I do the above procedure with both my 2013 Prius and my 2014 RAV4. No sense having rusted out hitches. I actually lubed the bolts and once the hitch has been removed, I screw the bolts back into the holes so the holes don't get corroded. Highly recommended. Both of the hitches look new.

 

I try to use up what I've got sitting on my shelfs, avoid buying every more products. Just less crap for my kids to deal with if-and-when.

I finished off a spray can of rust-proofing lube a while back, was casting about for something to use, and lit on an old can of 3-in-1 oil I had on hand. Now whenever I take a bolt or screw out (license plate bolts for example) I just put a drop of that on the threads. I've got a couple of cans of WD-40 kicking around too. It's sort of the "duct tape" of the lube world, but meh, will try to use it up too. Then there's a couple of tubs of grease. There's lots of options.

 

Why do you want to take the hitch off in the winter?

 

Looks like good stuff, similar to the can I just finished off. At my age, with all the odds-and-ends oils/greases I have kicking around, my strategy is to try to use up what I've got. For lubing fasteners, most anything will do. There's some plastic panels on the underside, towards the rear, that are held on by 10 mm (socket size) bolts. If you get ambitious, try backing those out and soaking them. I found on ours they were nearly seized.

 

Bought the hitches in the same week I purchased the vehicles. No loctite. Make sure to torque the bolts (80lbs I think), but in some years I just tightened the bolts as tight as I could. I only use loctite on my motorcycle bolts. Lube = grease. As others have commented, in Minnesota there is lots of snow/ice and therefore salt is used on the roads. Trailer hitches rust really quick in this environment and look terrible. I have got it down so I can install/remove both in less than 1/2 hour. Works for me.

 

A bolt holding nothing but itself would be safe as houses. I would just nominally torque it, say 25 ft/lbs at most. One issue: oiled threads make it easier for the bolt to turn; if they're still oily when you put the hitch back on, I'd suggest to reduce torque say 20%.

 

I would do the final tightening of just the bolt by hand, with a ratchet wrench, just tighten it firmly. If you're installing the hitch with a specified torque value, using a torque wrench is good practice. You want to avoid using them at values near their extremes; a 3/8" and 1/2" drive micrometer style wrench will cover most needs. You can find decent quality import wrenches on sale for around $30.