I've never felt the need to rotate even VDSL suppliers.
Whilst AAISP is an expensive supplier, you get what you pay for, so I'm more than happy to pay for it - I have my reasons for using it.
Bulk traffic, I send down my Sky FTTC line, and that costs me... I think £21 a month for Sky Fibre Pro. (Negotiated that for 18 months, but still, it's a great price for what I get out of it)