Make sure you change the anode in your hot water service every six months. Probably one of the most important maintenance jobs.
I usually put the van in for a full under van service every 12 months when it goes in for a pink slip.
We use the T Bags for our toilet, works for us and a lot less messy. All the other stuff you treat like you would treat anything in your house

if youre not using your van for months and its sitting in the driveway, many people jack it up off its wheel and block it under the chassis to take pressure off the tyres - also cover the one that's in the sun all day with a piece of ply or even canvas (don't use a plastic tarp as it will rattle in the wind and wake you up at night)

Don't put grease on your tow ball - dust ad grit will stick to it and wear it out as well as making a terrible noise. There are some on this Forum who swear that an ordinary plastic bag (like a supermarket bag) put between the tow ball and hitch of your van acts like a lubricant and saves wear and tear. Yet to try it

We have a S.S hot water cylinder so it doesn't have an anode - but we do drain it when not in use - s.s. rusts as well

We use the same household products to clean the stove top, grill, oven and shower. Many use napisan in their toilets and swear by it having used it for years both for cleaning and to dissolve waste. Be careful to avoid this while the toilet is under warranty as you will void it. We spray all the rubber bits of the toilet once a year with olive oil spray to keep it freely moving, clean the bowl with normal type toilet cleaner - nothing too harsh and a newish product out called Porta Pack. These look like oversized tea bags and smell very sweet. Just drop one through the toilet with about 1.5 litres of water and they will dissolve anything, including 4 ply toilet paper (don't waste money on the bush pack ones they sell at Dealers shops and camping shops). The little bags come in different colours and smells. Only use the blue ones if you want the job done properly. They are made in the USA and distributed nationally by Camec (a major RV parts supplier). Buy them in most caravan and camping shops. Don't pay more than $20 for a pack that will last you (depending on the efficiency of your bladder and bowel lol) for about 2-3 months. If you choose to waste money and buy Thetford liquid - then only use the blue one - the others do a poor job of dissolving solids (just like our tea bags - and no we don't mix them up when making a cuppa as the toilet ones and very strong, sweet smelling !!

I believe these sachets are what is being referred to as tea bag's.

http://www.bcf.com.au/online-store/products/Bio-Pak-Express-15-Additive-Sachets.aspx?pid=293195&menuFrom=571626#Recommendations

It becomes very confusing when the correct terminology is not used.