Check the quotes you have on file that are yet to be actioned. Do any of these quotes need to be progressed in the coming year? If so, you have a fixed cost you can add into your budget to help inform a variable cost. Using quotes its a brilliant way to help you budget. Ask contractors to quote up work in advance of your budget and not only will have reduced your variable costs, but you will have a fully costed plan of work to justify your budget and communicate to your customers.