Depends
2 of us here, and 2 kids most weekends, and only I do the laundry.
Normal week around 10, bad week 20+
Can't really pin down individual loads, I just do them as needed, ALL days of the week the washer is on 1 time a day at least, maybe 5-6 times a day on a bad day (when have the time).
Even though we have a LOT (and I mean a lot of clothes), I still wash a load when it is ready.
The main probable cause is that, no matter how hard I try; I just really, really cannot bring myself to use a towel more than once, I just can't do it. To me, it would be like putting dirty clothes back on after a shower. Of course it works for others, which is great. If I was lucky enough to live in a drier climate then it maybe different - I live in North West England, so it's never going to pan out well.
Also, very conscious of what gets loaded together; example there is no way, on this Earth would I wash kitchen linens with anything else.
Only the one washing machine.
Remember as well, our washers here, don't reach the capacity of MOST of the ones on the US market.
Our washers are rated in KG weight, as opposed to Cu.FT, but on conversion, I don't think you will find a UK washing machine bigger than 2.5 Cu.FT in a domestic setting.
I hope that's right, as I just found out a UK Gallon is bigger than a US Gallon, which surprised me - I'll hold my hands up, it was practically fully metric here by the time I was schooled so only know Milliletres/Litres Grams/Kgs, and CMs/Metres. So cannot be exact on what ours are in Cu.Ft.
My washer is liked below.
http://ao.com/product/wf90f5e3u4w-s...des - Washing Machines - API&WT.z_AG=Samsung