How long will Charcoal or Briquettes keep stored

How long would restaurant grade charcoal and quality briquettes (heat beads) keep if stored dry in a garage/shed. I'm assuming a year or so would be OK.
The problem with quality fuel is that after investigation there doesn't seem to be anywhere within a reasonable distance to me that stocks good stuff I can buy off the shelf. This means ordering online so to get a good value for delivery costs and save having to arrange someone to keep having to be in it makes sense to put in a size able order especially when talking Charcoal. Heat beads can be got in orders of 4x 7kg bags but Charcoal looking at 9x 15kg bags for free delivery.
I know I can get Weber fuel at most garden centres but want to try some of the other recommendations.
If I order 10x 15kg bags and it took me more than a year to get through would that be an issue. Mainly fuel for a WSM and I'm not just in it for summer.
How long have you keep your fuel for? and it still be useable?
The problem with quality fuel is that after investigation there doesn't seem to be anywhere within a reasonable distance to me that stocks good stuff I can buy off the shelf. This means ordering online so to get a good value for delivery costs and save having to arrange someone to keep having to be in it makes sense to put in a size able order especially when talking Charcoal. Heat beads can be got in orders of 4x 7kg bags but Charcoal looking at 9x 15kg bags for free delivery.
I know I can get Weber fuel at most garden centres but want to try some of the other recommendations.
If I order 10x 15kg bags and it took me more than a year to get through would that be an issue. Mainly fuel for a WSM and I'm not just in it for summer.
How long have you keep your fuel for? and it still be useable?