It's very important to take care of your bags, backpacks ... like all organic material, it will always appreciate that you pamper and take care of it.
A very simple and easy-to-apply trick is to hydrate your pieces with moisturizing cream, I use the one from the Nivea blue jar.
* You can first clean the surface with a damp cotton cloth and then apply the cream.
You will see that first its color rises a little, don't worry after a while the leather will absorb the cream and it will be as new and hydrated.
I do this ritual annually with my leather boots and sandals.