Rental properties will need repairs just like any other home. Heating equiptment will break, appliances need to be replaced and fixtures will wear out. You don't want to be surprised when these things need to be repaired or replaced and have to rush to get them fixed. This could potentially leave you paying a higher price then you would if you had time to shop around for a better deal. Complete routine inspections of your property and plan for all major repairs and changes. Shop around to get the best prices or quotes and choose the best offer. For larger repairs this could save you hundreds or thousands of dollars. If you need a new roof and you wait until water leaks into the house, your tenants will insist on getting it repaired right away.
Another expense you can avoid is paying top dollar for replacement parts or supplies. Shop around and buy things in bulk when possible. Look for sales on paint and other supplies and plan those repairs when you can get a bargain. Light bulbs, fuses, filters, cleaning supplies are all thing you can buy on sale or in bulk at a discount. Stock up on these things so they are there when you need them.
Manage your tenants. Make sure they abide by the terms you set in your lease and enforce them. This will help you to avoid fines by the city or undue repair costs. Check up on your tenants often and make sure they are putting the garbage out and keeping up with their household responsibilities. Make sure you get all of your keys back before you return the security deposit so you don't have to pay for replacements.