What do you infuse?

What sort of gear do you find worth infusing? Where do you draw the line of what could be useful later or this helps me now?

Spawn has given me 5 SSR helms to mix and match on my lancer. I'm currently using 2 28 cost Magic Armor Ups and a 27 cost Phys Reflect along with the Apollo Helm. I just pulled the new 28 cost headgear and am thinking about infusing that into one of the passive 28s for the stats. I also have a cheaper 25 cost, so even easier infusing there. What would you consider most efficient? Basically, what guides your infusion decisions?