Like lxt and fireman, I too have sold my bucket truck and opted for a towable unit. I got tired of all the maintenance on a truck not to mention the licensing and insurance costs. Trucks are great if you're going to use them day in and day out but, if they're going to be sitting around inbetween jobs, a towable or self-propelled unit seems like the way to go IMO - less overhead.
Like John said, make sure you charge for the truck. I always quote my jobs with the following items: 1) Labor and basic equipment (per man) including a pickup, saws, ropes, etc., 2) Heavy Equipment including aerial lift, crane, loaders, dump trucks, etc., 3) Hauling and disposal fees and 4) mileage outside of a set area.
I track each of these (along with subcategories of each) through my Quickbooks software. At year end, I can see what my income is for each piece of equipment and compare that with my expenses (loan principal & interest, insurance, licensing, maintenance, etc) for each. If my income doesn't meet or exceed my expenses, I have to analyze whether it's worth owning that piece of equipment vs leasing or renting.
A nice bucket truck can increase business by providing advertising and helping your crews to work faster. However, any sound business investment needs to be backed up with good book keeping so you can always look at what your bottom line is.
I am constantly re-analyzing how I can work more efficiently with the equipment that I have. As an equipment 'junkie', I am always wanting to buy more equipment; however, as a buisiness owner, I still have to justify each and every purchase...