I like to write at night, after dinner and little time on the couch watching something mindless on TV.
I pick up my laptop, check my tweets, posts and gmail and then open up my latest project. I dump my notes from the day that I keep in EverNote on my phone and I'm off, plowing in the fertile fields of my imagination.
One of the things I'm learning, that you may or may not already know, is that ideas don't come at convenient times. The Muse is always active, always 'tinking and, well, musing. She has no time table, no agenda, no sense of 'now'. She just does her thing when she feels like it and then taps you on the mental shoulder. 'Here. What about this?' Then she moves on, tiptoeing through your mind, looking for more goodies to create with.
So I'm advocating that you get something like OneNote or EverNote and make it a habit to write down those flashes of inspiration, good and bad, whenever and where ever they appear.
Then, during your 'normal' writing time, review them. Add them, play with them, chuck them, whatever you think best.
Just don't ignore them.
Ideas come to you for a reason, even if you don't immediately know that reason.