I am a Pet sitter and recently saw maggots at the bottom of one of my customers cats food bowls!!

I realised this was due to the window being always open so flies lay eggs in the wet food, which becomes smelly if not eaten during the day so...
I recently (within 2 weeks) changed my cats from 11 years on wet food, to just dry food (and a little pouch every other day as a treat)
In the first week I used Purina (£2.99 on offer at Tesco) and although they turned their noses up for the first few hours, they soon got used to it and I found they ate less. This week (the second week) they have Iams, again at £3 (£1 off offer and £1 off coupon), and they seem to like Iams more than Purina
So so far its been £6 for 2 weeks worth which is waaay cheaper than wet food. Plus I'm happy that their teeth wil be a lot healthier now.