What size backpack for a years travel?

Quoting CheersT

Personally your style of travel would be hell for me - I can't imagine fitting your stuff onto a motorcycle or into a dugout canoe

I have actually even managed it sitting on the back of a little scooter being driven into Chiang Mai by a friend who was living there. Was admittedly somewhat precarious, but we both survived. *g*
But yeah, overall my travel style relies more on regular bus / rail / car connections for local transport, and on the few occasions I go for multiple days into untrodden parts, I'll leave the big bag in luggage storage at accommodation somewhere, and do just that part with only the daypack.

Wow thanks for all the comments everyone. I suppose yeah everyone is different and have different travelling techniques.
So if 45l is big enough I think I will be taking that size, I was just wandering if any1 knew if that means the size is small enough to take on the plane or whether it still has to be checked in as luggage?

56x45x25cm is typically the size limit for cabin baggage for long haul carriers but any airline website will tell you theirs exactly and whether they also specify a weight limit.

Ok great thanks andy

Late comments. I have not tried a year of travel, my longest trip is only half a year. If you can replenish the items you need on the road, I think the 45-50 liter backpack is enough. At the same time, I think this is a reasonable weight that the body can afford. By the way, if it is a charging backpack, it is more convenient to charge electronic devices such as mobile phones that need to be used frequently.