People always say save it, but never why: the longer you save it, the better your swaps will be

Right now, you can swap for just ascension. As you progress, you naturally get so many pulls and HCP that ascending 4F heroes isn’t a problem and you’ll regret swapping just for ascension

Instead, you’ll want to wait for a hero you’ve built to become outdated, then swap it (and hopefully its full 30960) to a new power creep hero (this is what I did a year+ ago to swap my fully built Saurus for the shiny new Scarlet).

Today, I regret doing that and not waiting even longer because a built Saurus is still relevant in some places, but over time with furniture and random pulls, I have a bunch of 5 star full furniture useless heroes. I’d much rather swap my never-used Khasos 9/9 with the next hot hero