Hank93
Brownlow Medallist
From memory, someone said that Hawthorn and Puma had the longest deal just after they announced they were changing to Adidas.
But many people don't get numbers on their jumpers. Personally, if the jumpers get a new template or collar, I like to buy a jumper for it, but I tend to wait for the next year as the team normally changes their clash at then (eg ISC)
Being a jumper collector I've purchased every Crows home jumper since 2006.
Every time the template changes, I'll go and grab the new one (and generally the player worn version).