Don't buy normal trousers belts, instead buy elastic belts which can last literally for life
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I just started making my own belts. Most leather belts are made of thin veneer of leather. It might even be marketed as 'top grain leather" to make it seem special. Get whole grain leather.
I bought parts from one of the last Tandy Leather retail locations. Brought them home and used my hole punches I picked up at Harbor Freight for a different project and some grommets I got for a different project and made a belt. Out of pocket cost was maybe $16. That belt will last me decades.
In theory I could knit some belts with any number of sturdy materials like leftover metal cables but I have never felt the need.