How do you know if you're a good landlord/property manager?

[Edward Norman]

Whenever things come up or problems arise,  it's easy to get down on yourself and take the blame, whether the issue was within your control or not. 

with that said...

what are some indicators or measures that you use to track performance against? And how do you know whether to attribute performance  to 1) the property/condition , 2) the tenant being rough on the property 3) cost of doing business, normal occurance

off the top of my head I'm thinking:

Days to close out an issue

Timeliness in responding to issues

Annual/quarterly repair expenses

# of repair request per year

Or even how do you know whether or not your getting better at landlording /property management over time? I may be over thinking this but wanted to get you all's opinion