Do I need to cut my girls' toenails? If so, how often?

Er... that's it really.  Do I need to cut them?

Their had their toenails trimmed when they were given to us, by the BHWT, but I don't think I am clear as to whether that was a one-off when they took them out of their cages, or whether it is an ongoing maintenance issue  

Their nails (?) aren't that long at the moment (1cm or so) but it is just something else that I can worry about...

was just typing the same thing.  i check my batts , but they haven't needed a trim since rehoming a year ago.