I also have 5 kids and a dh, all of whom can make mess for England!
One trick I have learnt is to focus on one or two specific areas which you want to stay looking nice. ie kitchen and lounge so whenever anyone comes round the illusion is that everyhwere is spick and span.
I concentrate on keeping the kitchen surfaces clear, the sink sparkling and the floor swept and mopped. Then I make sure the lounge is free of clutter and swpet and the suite wiped over. I don't worry too much about toys being put away until the little ones go for their nap, then I have a tidy round - same again at bedtime. I always have one last 5 minute clear up before I go to bed so all is clear when I come down in the morning.
You seem to have it well sussed with the kids tidying up after themselves - maybe enlist their help as well for half an hour every few days - stick some loud music on and all of you whizz through the house cleaning and clearing as you go. Reward this with a small treat to make it worth their while!
I don't tend to have a routine really, just do what needs doing as I see it but concentrating on the kitchen, lounge (oh and toilets) seems to keep on top of things!