Do agents who read partials usually comment?

I spent the last several months writing a creative nonfiction book. I have a BA in creative writing and literature but it has been some years since I have been involved with writing. I have published some articles and as an undergrad I published 3 short stories.

I am in the process of sending queries and have had some interest. When an agent requests a partial, and I send it, I am understanding that I may not hear for quite some time. When I do, is it likely that the agent will offer comments or does that depend on the agent?

thanks in advance,
feeling foolish as I learn the ropes

that makes sense- depends on agent and on the quality of the partial.

I remember being taught in school to plaster the wall with rejections. It makes it seem fun. I remembered the advice and was actually excited about my first rejections. I had some requests, too. Actually, I'm rather amazed at how nice some agents and editors can make a rejection sound.