How often do people clean a mattress protector?

[Bubbaloo]

I recently bought one with a new bed and never having one before,have no idea how often they are meant to be cleaned.
Thanks

Is it just like a padded fitted sheet? I wash mine whenever I change the bed.

my mum has one which is like a big stocking which she only washes occasionally, but it takes her about a day to get on and off

mine is just like a fitted sheet so it gets washed when the sheets do

Yes,mine is also like a padded fitted sheet so looks like I'll also need to change it when I do the sheets.Thanks.