At the end of every year, your uniform allowance becomes use or lose.
Minimize the allowance slightly and allow for rollover of unused moneys, and people would feel less compelled to spend it, and may even promote the saving of unused moneys.
Also implement uniform recycling.
I once tried to return a bunch of old uniforms, that no longer fit, or were unused because they weren't the right size. I was not looking for any sort of refund or reimbursement. I just wanted to return the uniforms so that the material and patches could possibly be recycled, and reused. They sent it back and told me they could not accept the return without the original invoice, and had gone past the return date anyway.