Has anyone had issues with renders that didn't finish? I'm wondering if its because of the environment change - I'm playing around with HDRI, but more than a few hours (and still not done) seems a bit much.
There could be a few reasons for this.
Do you experience this with all of your scenes or just a few in particular?
The most common reasons for this are either lack of available GPU/CPU, or complicated scenes with a large amount of geometry, animations, textures, etc.
Multiple HDRI environments can also cause your renders to slow down.
Stopping any other CPU heavy programs and lowering the scene's resolution will help. As well as deleting any unnecessary textures.
Make sure your computer is running on Performance mode. Things as simple as restarting your computer will clear any programs running in the background and should improve your computer's performance.
Let us know if any of these help.