I clean and disinfect my bird feeders with F10 disinfectant about 2-3 times a week. Mostly though, I scatter peanuts and seeds around the garden in different places each time. I do only put out food 3 times a week also, if I put some out every day then the 6 wood pigeons simply stay in my garden all the time, only leaving if the fox comes by.
The corvids get their food from my puzzle feeders that I put up specifically for them, these also get disinfected 3 times a week.
I've found the local birds have gotten into a routine with my garden. The magpies and wood pigeons come around most frequently since they both nest in nearby trees. The mob of house sparrows and finches visit when the magpies are elsewhere. Curiously, they also visit when the crows are in the garden. The crows don't seem to bully them like the magpies do.
The garden is rarely empty, the only time there is not a wood pigeon or a corvid is when there is a predator around - we also have a resident sparrowhawk and a frequent buzzard now.
The main reason, especially in summer, why my very urban garden is constantly busy is nothing to do with food I've found. It's because I have a pond. They all come for the water more than anything else.