at leisure
• not occupied; free.
• "the rest of the day can be spent at leisure"
• in an unhurried manner.
• "the poems were left for others to read at leisure"
at one's leisure
• at one's convenience.
• "wander at your leisure through the wide selection of shops"
Similar:
at your convenience,
when it suits you,
in your own (good) time,
when you can fit it in,
without need for haste,
without haste,
unhurriedly,
without hurry,
when you get round to it,
when you want to,
in due course,
