Repair a leather strap

Leather wears out over time, your strap Isn’t fixable, replace it.

Will defer to our leather experts like @Duracuir1 … but… You have a nice watch at risk IMO.

I had success using the open weave fiberglass stuff used in patching to repair a pigskin strap. Barge cement (shoe glue) is great at holding the peieces back together once they have been cut apart. I had to resew it. The tricky part was the buckle as it does not use a springbar. edit: I find the thinnest beading needles work the best for re stitching. There are plenty of YT vids showing how saddle stitching is done.

Saddle soap can some times help with some leathers. Most of the time in the pipe organs they sort of become like tissue paper. There is some stuff which is red chrome tanned, which is as good now as it was 100 years ago. Although 50 is closer to the usability. Much of the modern pipe organ leather used is Kangaroo. Which uspsets the PETA people. Sheep and goat was the traditional. Ironically Kangaroo is not supposed to be sold in this state. I do not think anyone notices or really cares.

The laser is great for cutting out straps. I now have a lot of them to sew. A problem when learning a new skill that the projects increase. So one quickly become many. The laser can quickly produce blanks. The sewing takes time.

Buckle hardware is a subject in and of itself. Most suppliers do not sell much below 16mm.

I don't know what I'm looking at in those photos, but the strap doesn't look like it's about to break, so maybe you should just keep using it. Eventually it will need replacement, because straps don't last forever.

In my shop I have the advantage of having leather dust from my belt sander. (Usually collects where the arrow in my photo points).

Mixed with glue in just the right amount and then burnished.

Or you can buy a pre made solution on Amazon.

If you like your patinated strap, buy a new one from the same maker and put yours aside as is. Use it on special occasions. Your new one will age with use.