Anyone start using sleeping bags at 8 months ish? Any alternative?

[IsleOfRight]

With dd used sleeping bags from six weeks until a year. Not used at all with ds as somehow just got into habit of blankets and he liked that. He's about to go from crib to cot though - is it too late to introduce sleeping bags do you think?

Watching with interest. DS was swaddled in blankets for way too long (wouldn't sleep without it) and then we co slept. But now he's in his cot and he seems to spend the whole night moving around, so I think blankets or a quilt (he's 12 months) won't work. It's going to start getting too cold for me to just put more layers on him! I'm terrified of jinxing the good sleeping he finally started doing after 9 months of hell, and I worry that because he likes to move around so much a sleeping bag will keep him awake, especially as he's never really slept in one apart from the odd nap when he was a lot younger I really need to bite the bullet and try soon, but it makes me stupidly nervous! He was a truly awful sleeper for a long time...

I introduced it at 7mo and it went very smoothly. DS wouldn't sleep without being swaddled. He resisted a sleeping bag at 6mo and then at 7mo when I he began putting his shawl over his head I tried again. The first night I swaddled him and then putt he sleeping bag on him (it was Winter) then the following night I just did the sleeping bag. He still needed his shawl as a comforter but he slept well which was not what I expected.