Prop Owners: Tenant credit check service?

Question for smaller investment property owners: Which tenant credit/background check service do you use? I looked at a few online and they all require paperwork (proof of ownership, canceled business checks, leases, etc...) before you can open an account. Stupid question: I'm assuming that we would enter ALL of our buildings during sign up? How long does the whole process usually take before you can start running credit/background checks? I manage my family's small portfolio of commercial and residential investment properties in the NYC area. Most of our tenants were referrals so we never needed to run credit checks. Recently, we had a couple of applicants who were not referrals so I'm curious what other owners do. Thank you in advance. V65