[lmilcin]

Write down. Make a system which you can trust you can come back to that thing and think about it.

When I drive and listen to an audiobook, I sometimes have to stop, make a note, and only then I can keep driving. If I don't stop to make a note I am going to miss either the rest of the audiobook or the idea I just had.

Writing the idea down lets me safely "park it" for later and focus on the rest of the audiobook.

This only works when you can trust the idea comes back when you can do something about it.

I am using a compromise/modified GTD (Getting Things Done) system. I have a bunch of folders for my projects and each has special NOTES document where I write down anything pertaining to the project. So the next time I come back to think about that project the idea/task/whatever I just wrote will come back to me and I will be able to do something about it.