The wake ups are likely to be hunger related. All of them.
By that I don't mean baby is starving hungry every hour or so. However if total calorific intake over the previous 24/48 hours is on the low side, it causes light sleeping.
It's entirely reasonable that some babies at 5 months old are receivibg all of their calories during the daytime, so never need any feeds during the night. Such babies are also more likely to have higher total calorie intake so that allows them to "sleep through"
Sleeping through effectively means sleeping deeply. A light sleeper wakes frequently, a deep sleeper doesn't.
So the dummy has nithing to do with being a kuggt or deep sleeper. The dummy helps a baby settle to sleep when they wake up. That is the beginning and end of it. If you have a light sleeper, waking frequently, there'll be lots of dummy reinserts. If you have a deep sleeper, there may be a single dummy insert at the beginning of the night and that's it, no other wake ups.
Two key factors affect light sleeping:
- total calories over 24 hours
- total sleep over 24 hours
Make both as much as possible. Lots of big, frequent daytime feeds and naps.
Dummy is inconsequential to the frequency of wake ups. It's just a means to get baby back to sleep when he does wake. A very easy way too.
By about 7-9 months babies can learn to reinsert their own dummy. So even if you have a light sleeper still at that point, you may be needed less for reinsertions.