How to determine qualify of Roofer's work?

[Basit Siddiqi]

Thank you in advance for anyone who provides answers/feedback to my question.

How can one judge the quality of work for a roofer?

I recently got new roofs on 2 different investment properties and I can't say for certain that I can judge the quality of the work.

It recently rained and the water did not go through so that is a good sign. But how do I know that it was a really good patch job and water will start leaking in a year?

Unfortunately, I don't feel safe getting on a ladder and going on-top of the roof.

Should I hire an inspector to have him give me his feedback?
Should I ask what materials were used for the roof?
Roofer said he provides a 10 year warranty for the roof - is this an indication of a good roofer?

Any other feedback will be helpful.

Thanks,

Basit

*edit* sigh - I meant to type "quality" instead of "qualify" in the title...