Patch your pants
A good formula for guaranteeing ripped clothes is buying a somewhat tight pair of pants from any fast fashion brand, cycling daily, and letting these pants be your only pair for all occasions — weddings, bar mitzvahs, swimming, etc.
To fix: cut a piece of cloth from the other pair of pants, pin the patch inside the hole of the pants you want fixed, and go nuts with some needle and thread.
Instructions
References
Video: Invisible mending - How to patch a rip or tear in jeans and pants
Article: How to fix holes in Jeans
"Most of the fixing of holes in jeans involves sewing a patch that will cover the hole. A patch is an extra piece of fabric attached on another fabric – this piece of fabric should be large enough to cover the hole – it can be matching the base fabric to blend in or a contrasting one which will stand out."