Sucking finger/thumb, good or bad?

My 3 month old baby has just discovered his finger/thumb. He is now what seems like continuously sucking at them to self settle or re settle himself to sleep.
Prior to finding his finger/thumb he would sleep 12hrs over night (bliss) and wake around 7.15am for a feed, then feed every 2-3hrly during the day and would get around 4-5 feeds.
Now he has found his finger/thumb he had still been sleeping 12hrs overnight until.... last night he woke at 2.30am. He was wrapped in his Miricale blanket as he has done for the past couple of months. After much rocking I gave in and gave him a 5 min feed which did not seem to settle him until I unwrapped him and re wrapped him into a blanket he could get his hand out of and started sucking away. My problem is, well not sure if it is actually a problem, I have to wake him to keep his feeds to 4hrly during the day cause now when he wakes during the day he will self settle himself back to sleep by sucking at his finger/thumb. So tonight I have put him in his Miricale blanket however I left his hand poking out the top so he could suck his finger/thumb. Not sure if I should be doing this but I am scared that he is going to start a bad habit of waking up from not being able to suck his finger/thumb.

Is the sucking of the finger/thumb a bad habit at this age, or should I be happy that he can self soothe by this method?

My girl's a thumb sucker and I love it! I always wrapped her with one arm out so she could get it, it's always there and she can't lose it in the night, she only sucks her thumb when she is tired or hungry, which makes it easy when we're out and about because people can see when she's tired, it's free, she gets a good healthy dose of germs off it, and she'll grow out of it (much easier then trying to wean off a pacifier). I spoke to an orthodontist about it and thumb sucking has no impact on teeth until about age 7.

if you are worried that he is sleeping too much in the day maybe you could make sure he cant get to his thumb, just leave it out at night...   

Count your blessings!!!
Mika LOVES sucking her fists, sometimes she does it so loudly I can hear it when I'm in another room.
As far as I know it is really normal for babies to start sucking their hands and thumbs, it's part of exploring their bodies. And it's great if they can self settle this way. Mika settles herself well at night, but unfortunately does not seem to remember this skill during the daytime
(By the way, I haven't wrapped her since she was a few days old, as she never liked it. But I reckon it's a good idea for you to leave Cooper's hands out so he can use them to settle)

Sounds like Cooper is pretty perfect to me! I wouldn't worry about the thumb sucking until they are a couple of years old. It is great that he can self settle (I would love it if my girl could) and his sleeping patterns are just amazing. Sounds like you are doing a great job! Maybe you could share some sleeping secrets!

Speaking from experience as I was a thumb sucker and I sucked it way too long . I wished my mum and dad had stopped me sucking my thumb when I was little but they didn't and then when they did try it was so hard and stressful, I remember it well... But I have the best teeth out of everyone in my family and I was the only thumb sucker. Everyone else needed braces.