Large suitcases, large backpacks. Probably the worst thing about traveling. So what to do with luggage storage?
Several times in the past, I have traveled with large pieces of luggage because my trip had several purposes. I would go hiking for several days, but would still need casual clothing for the rest of the days. I would do a small city trip while being in another country. I would do a round-trip where I need a suit in one city, but not in the other.
In all cases, it was inconvenient to bring all my luggage with me along every single step of the trip.
So best, solution is -if possible- to plan the same hotel before and after. So: arrive in a city, where you book hotel A, then make the hike/city trip/extra stretch, and then return at hotel A. At hotel A, you leave the stuff you do not need for the middle stretch in a closed suitcase. This will save you the money for dodgy and insanely expensive train station luggage storage or expensive airport luggage storage. Both of which often are full.
The only thing you will have to do is ask your hotel nicely and ideally beforehand.