It’s quite simple: Almost no matter how long a trip you plan, bring tools, food and extra clothes.
Tools
Only bring tools you can figure out how to use yourself.
For the short trip – the basic package:
Pump
Puncture kit
For the long day trip – the midi package:
Mini tools for bicycles
Extra hose
Plastic strips and a meter of DUCT tape for emergency repairs
For a cycling trip – the maxi package:
Cable cutter
Nipple wrench
Chain tool
Gear and brake cable
Chain link
Oil or wax for the chain
Disposable or work gloves
Remember: The easiest way to avoid needing tools is to give the bike an inspection before the trip.