I have a lad that works with me 2 days a week, my son runs the 2nd van on those 2 days so we basically work with staff 2 days a week, with each other 1 day and every other week I'm on my own for a day with the following week off for a day.
we find it works well because you're not stuck with the same person every day and you get at least one day off a week or a day to work on your own. it suits the 2 staff as well as they are working 15hrs a week so only registered as part time, it saves on holiday pay also (as 5 weeks @15hrs - we give them an extra week each year).
after el insurance,wages etc each member of staff makes £70 a day for the business with a further £65 wages (they would normally do £150 - £180 a day each).
we could push them harder (a lot harder actually) but they are very good staff, never late, never any excuses from them (have had to send them home in the past for not being well enough to work), friendly, superb with customers too.
My son and I gave them both a small bonus last year (September), a hundred and fifty quid each,( bearing mind they only do 15hrs a week) since then they have both worked saturdays when we have needed them (4 times).
I know some wouldn't treat staff the same, others maybe pay more but overall I think we are pretty good to them and they repay that as best as we could ask.