User blog comment:Swag219/Hey guys, can someone tell me Is it worth saving gems for new units?/@comment-28705539-20160711174400/@comment-26947994-20160711190717

I would say only summon when you absolutely need to replace one of your units, like when one of your units is unusable in the game because it is too weak. This is because units will keep getting more powerful in the future, so a unit today will probably be useless one year later. For example, Six Pillars batch was really powerful a year ago, but now no one uses them because they were the first batch of 7* units and there are units that do the same thing but better.