I had a
bad experience last weekend when I went to resize the bracelet for my new Seiko watch.

The bracelet is using collar + link pins which I've never done before, so I decided to go to my nearest watch shop.
I ended up with a damaged collar, small scratches on bracelet AND the bracelet wasn't even assembled back.
After seeing the way she mishandled my watch I quickly told her to stop and took the parts home.

With the help of the almighty internet, I managed to refit the links myself.
Eventhough I had to make my own tools by filing down an unused precision screwdriver, I did a pretty good job (No scratches and properly fitting collar)

Not only that, but I ended up resizing another watch I had at home, just because I could.
So, the lesson learned is:
1.
When possible, do it yourself. Hardly any watch shop owner will bother to take his/her time to make sure your watch will emerge unharmed.
Its good practice and it saves you time and money.
2. If not,
bring it to a well established watch shop. Warning signs are when they don't have any specialized watch tools like proper pliers, spring bar tool , link pin remover etc)
There are plenty of tutorials out there on the net, go ahead and give it a shot!