My wife’s yoga teacher suggested 3 grams before bed for sleep, but we didn’t notice a significant difference. I do know that Frank Zane wrote about using glycine as a sugar substitute in his iced tea because it was so sweet-tasting. I never got around to trying that, but I’m sure it couldn’t hurt.
This talks a bunch about it:
Yep, every day should be fine.
It’s a simple amino acid, so I wouldn’t expect there are interactions.