Affirmation decay?

Was thinking about how we are advised in tutorials (DILD, MILD etc) to repeat an affirmation for as long as possible before we fall asleep. In my own experience, I've found that my affirmations change on the journey to sleep - they change into different words, become nonsense-speak, merge with HHs etc. Could this be counterproductive? The last thing we'd remember would be a nonsensical affirmation. Would it make more sense to repeat an affirmation for as long as you can until you start to fall asleep - and find the affirmation starting to "decay" - then say the affirmation one last time clearly then just let you mind clear and surrender to sleep?

I understand what you are saying. My mantras usually don't 'decay' as I fall asleep. It just takes some practice to be able to think the correct mantra as you fall asleep.

Hmmm, I usually stop repeating mantra's like "I will be aware when I am dreaming." at a certain point. But the thought is still there, so I'm still know what I have to do, but not the exact words as in the mantra.
So its more about the intention then the exact words for me.