grobags - necessary?

[ch1134]

I have a 3 week old son and am using blankets for sleep as was told grobags not safe until their heads are bigger and won't slip through.
Now I'm wondering, why change? I heard grobags keep them at the right temperature, but I can't help thinking it's nicer to sleep under a blanket.
If we did get grobags, surely we'd need loads - different togs, different sizes and one for the wash of each? So could I save some money by not buying something unnecessary?
Thanks

Thanks, useful advice!

Don't buy the expensive grobags, you can buy baby sleeping bags somewhere like asda for a lot less cash. Definitely worth it. Dd is 9 weeks and in a grobag at night as she kicks the blanket off now and it's freezing.

They're great for my little wriggler. I got them cheap on ebay.