at will

at will AND at one's own sweet will — как вздумается, как заблагорассудится; когда заблагорассудится; когда захочется, в любое время; по желанию, как угодно, наобум
If you can do something at will, you can do it any time you want:

Example 1: He can cry at will.

Example 2: He can't just fire people at will, can he?

Example 3: The Crossmans' dog was a nuisance, and it was nearly always with them. Wherever it was, it yapped constantly, and they seemed not to care about the noise and would let it go on barking at will. They took it with them to dog-friendly restaurants, where it sat perched on Mrs. Crossman's lap, and when it took a break from yapping they amused themselves by talking baby talk to it.(Glen Pourciau, Snub, 2006)

see also
[suit yourself]
[do as you see fit]
[whatever floats your boat]
[according to one's own lights]
Have it your way;
As you wish

it's up to you to decide