This is something that occured to me a while ago but only just now actually affected me in game. When you have maxed out items you're incapable of purchasing and using an elixir (read: oracles) without first selling one of your items and then rebuying it afterwards. Obviously if you have several thousand gold to work with you can just sell your shoes, buy an oracles, use it, and buy the shoes again but when you need an oracles and dont have an extra 600-700g to do the sell/rebuy option, you're pretty much SOL.
Theoretically anytime I have 6 items (lets say Ive bought the components for a larger item and am waiting to get enough to finish it) but I need to buy an oracles, I cant without selling one of the items Im holding first?
This isn't Dota, I cant drop my items to use an item and then pick them up again or store items I need later at my base.