Try to be paid via billings rather than by receipts
Negotiate a short billing cycle
Annual leave will be paid to you upon termination if you do not use it
Align your leave with your billing cycle
If your billing cycle is longer than a fortnight, you may be financially better off taking leave without pay. In this way, your annual leave will be paid out upon termination at your base rate. Note that you do not accrue leave during periods of leave without pay.