Aegis is worth WAY more gold than you pay for it when youre with your allies, and even on your own iirc its worth 2100-2200 gold in stats, but only costs 1925, meaning that at all times you get more than what you pay for. Plus the Aura it gives to each of your allies is around 750gold worth of stats iirc, meaning that if youre with all of your allies, youre actually getting around 5k worth of stats...for only 1925. If you see nobody is getting it and youre either tanky dps/tank/support, get it, help your team win, even if they dont know they managed to barely live cause of that extra armor, or they barely killed their target cause of the extra AD. It may save that squishy Ashe that doesnt know she needs resistances to survive, its a very good item. The tank or the support should get it, but if youre tanky dps and nobody is getting it, do one good deed for your team and buy Aegis.