Whenever anyone wants to "help" it only takes about 5 or 10 minutes for them to realize just how much physical labor is involved. These muscles aren't from the gym. Numerous 50 pound bags of thinset, concrete mix, heavy boxes of tiles, a wet saw coming it ant 70 pounds, buckets of water 35 pounds each, ALL day long. And I think them manufacturers put the thinset in bags made out of tissue paper, so ya gots to be careful when handling them. Don't spill the water out of the bucket either. Be careful when you set the tiles down as not to chip the edges. We normally break a sweat unloading the truck.
I always find it best when a customer helps by:
1- moving personal items out of the way, empty the cabinet in the bathroom, move the vase from the entry hall table, roll up the rug in the foyer.
2- keeping pets and children at bay
3- the occasional offer of cold water / iced tea / coffee is nice
4- make room for materials and working
5- parking for the truck carrying the heavy materials
6- standing back and letting the professionals do the work they have trained for and enjoy doing.
7 -unlock gates
8- prepare a place for the garden hose to be attached and used. Move plants, BBQ pits, furniture to accomodate.
9- make adequate electrical outlets available. Those wet saws eat a lot of power.
These are all items that are great to help the contractor zero in on his job and not have to spend the first half of each morning prepping the job site to be able to get to working. And it saves you a ton of money, while protecting your stuff.
Now I don't mind a customer watching while I work. As we chat they find that aside from all the physical labor, its a lot more technical than they thought and there are a TON of tricks to the trade to make the job easier / better / faster. All of which can be quite interesting. Some customers have pulled up chairs to watch. That lasts about 15 minutes until they get bored
and all the questions get answered. I am not however, going to teach a customer how to lay tiles in half a day as I fear they will learn enough just to be dangerous and then have the excuse "well, YOU told me..." Ya know what I mean?