Using over the winter - do I need to winterize

Do not forget to bypass and drain the Hot Water Tank. DO NOT put any pink stuff in the Hot Water Tank or the Fresh Water Tank.

Yes, you must do it between trips.

Also, keep in mind when you return from warmer climates in all likelihood you will need to dump your holding tanks before you head North. Why, because the CO dump stations may be closed during the off season.

I prefer the pink stuff method. Once you do it a couple times it should take you about 30 minutes. All you do is drain all the tanks completely, Set you water pump to winterize and draw fluid from the gallon jugs through the lines. Make sure to get some in each drain trap. Your water heater should have a winter setting on the valves. You should get by with 2 or three jugs which you can buy for about 3 bucks a piece. Remember you are not filling any tanks with pink stuff just the lines and traps. Really easy and a lot easier than a broken pipe. The pink stuff is non toxic. Blowing out the lines works also I have done both but feel more secure with running the pink stuff through the lines. All though I haven't broke a pipe yet in twenty years with either technique. JMHO

and don't forget to put some antifreeze in the drain traps, etc.
bumpy

“Do I need to fully winterize and unwinterize the motorhome each time?”

The downside of not winterizing is the expense of fixing the RV if water freezes.

You have two options for the motorhome when it's in freezing weather (assuming it's a cold weather capable unit, i.e. the plumbing is enclosed within the heated part of the motorhome). Either you keep the motorhome heated above freezing, using say the furnace or by storing it in a heated indoor storage facility, or you winterize the plumbing system.

Winterizing isn't hard and the materials required aren't that expensive. If you have an air compressor and so can blow out the lines with air, the materials are downright cheap--just sufficient RV antifreeze to put a cup in each of the drain traps. If you instead displace the water with antifreeze in the pipes, it could be a couple gallons or so, still not very expensive.

I use the compressed air method with my motorhome. I start by draining the fresh water tank, the plumbing as much as practical with the low point drains, and the water heater; this means opening a few valves and the various taps on the sinks etc., removing the water heater drain plug, and then going away for several minutes while water dribbles out onto the ground. Next, I bypass the water heater, run the pump for a bit (to get water out of the suction lines and pump body as much as possible--it's OK to run RV water pumps dry for a minute or two), and hook up the compressor to the city water inlet via an adapter I pieced together. The compressor's regulator is set somewhere around 40 psi. Next, I successively open individually each of the taps and the low point drains and let the air flow until no water drops are spitting out, usually going around a couple of times. Then it's just disconnecting the compressor, shutting valves, and pouring a cup of RV antifreeze down each drain and into the toilet bowl, and draining out the bit of water I just put in the holding tanks.

All told, it's maybe a half hour of work and a dollar or two of RV antifreeze. Dewinterizing is equally as easy: put the plug back in the water heater, unbypass it, and sanitize and fill the water system. I do usually try to check for leaks beforehand with air pressure. The check valve in my city water connection vibrates when air flows through it, which makes checking for big leaks fairly straightforward: just listen for that sound.

the only way I know to not winterize properly is to blow out the system. then you stand the chance of water settling back into low spots. can do the winterizing the right way with antifreeze and drain and blow that out collecting the antifreeze for reuse. if you reclaim antifreeze I would blow out the system first so there is only a little dilution.
and no, the proper chemicals are safe
bumpy