Reply to best way to marking that this podcast episode number is listened?

Hi guys

I listen to a lot of podcasts from many different DJ.
I often get confused by asking myself "have i heard this podcast before? " and i hate to listen to the one that i already heard.
Now i hope there is a method (or App), that can help me to marking that this episode number is already listened, so that i will not waste time to hear it again.

Any ideas guys?