The old rule says: pack everything you think you need, then take out half. The trouble is that the wrong half leaves you at the side of the road.

Split the luggage into four: what keeps you in one piece, what keeps the bike running, what keeps you dry, and what keeps you legal. The rest is comfort, and comfort is the first thing to cut.

What keeps you in one piece

An approved helmet in good condition. A dropped helmet gets replaced, even if it looks fine.
Jacket and trousers with armour, gloves, boots that cover the ankle. In the heat you wear the ventilated version, not a T-shirt.
A back protector, if the jacket does not have a serious one.
Spare glasses or a spare visor, if you also ride after dark.
A small first-aid kit and your own medication.

What keeps the bike running

A puncture kit that matches your tyres (plugs or tubes, as the case may be) and a way to inflate: a mini compressor or cartridges.
The bike's own tools, topped up with the spanners you actually need: the axle, the spark plug, a set of hex keys.
Fastenings: zip ties, wire, strong tape. They hold a cracked fairing together as far as the first workshop.
Chain lube and a rag, if you have a chain.
Thin jump leads or a jump starter, if the battery has some age on it.

What keeps you dry

Rain gear that goes over everything you wear. You take it even when the forecast is good.
Dry bags for clothes and electronics, inside the luggage. No bag is eternal in four hours of rain.
A spare pair of gloves. Wet gloves are the surest route to a miserable day.
Something dry to put on in the evening, kept apart from the rest.

What keeps you legal

Licence, registration, insurance, passport or ID card, depending on the destination.
Copies of all of them, on paper and on the phone, kept somewhere other than the originals.
Your health insurance details and the emergency number, written on paper too.
A backup card and some cash, separate from your wallet.

What everyone carries for nothing

Clothes for every day. Three changes and one evening of washing cover two weeks.
Tools for repairs you have never done in your own garage. The roadside is not where you learn.
A second pair of shoes "for town", heavy and bulky.
A spare fuel can, in Europe. In the Balkans, Morocco or the Andes, a different conversation.

A good test: load the bike and do a 200-kilometre day at home. Whatever you did not touch all day you probably do not need — except the puncture kit and the papers.

If you pass a motorcycle shop or a workshop that got you out of trouble, put it on the map. Someone's packing list will be shorter because they know where to find the rest.