How much gold is worth waiting for?

So you just died/recalled and you are missing an X amount of gold to buy your next item.

For how long are you willing to wait to get this next item? 10gold? 20? 50? 100?

It really depends on the item of course. I would wait longer to buy a infinity edge then i would for a Ruby Crystal. But i usually draw the line if i have to wait more then 50 gold.