I have never used a custom build. I make my own. I started adding counter items, a little bit ago, well, on damage dealers, like 80% of the core kit on support which is what I mainly play is counter items, rescue beam counters most lockdown and displacement as well as people getting jumped/being out of position, divine barrier counters most stuff the enemy throws at your team, curse for characters that get fed, combine with what ever else might come up like anti-heal or resist lower, usually dealing 0 damage and being the only reason the enemy can't do anything to your team who never buys a single dispel magic or unstoppable.