Obviously I clean anything that spills or makes a mess, but I've had a couple of poached egg incidents this week, so thorough cleans more often than normal!
On googling how often I should be cleaning it, some articles were suggesting every time I use it, which seemed a bit OTT
I use mine mostly for steaming vegetables (lidded container), reheating coffee, microwave rice pouches - and said poached eggs, in a container when they don't explode.