What's your favorite tip as a landlord to save money and/or be more efficient?

[Andrew Freed]

I'm always looking for ways to be more efficient as a landlord. What is your top tip to save money as a landlord or be more efficient with your operations? 

I'm start.... I love leveraging the local landlord assocations for cheaper materials. At least in my area, my landlord association has a shared home depot account for their members resulting in serious savings. As much as 15-20% on orders. This saves me a ton in material costs.