I use dreaming city armor because of the enhanced weapon perks. The only time I infuse my armor is when I get a higher light level of the same armor ie dreaming city armor. When you do this it only costs 5000 glimmer. If I get a high level duplicate exotic I can infuse any armor or weapon of that type for 1000 glimmer and 25 planetary materials. As for weapons sometimes I will get the same weapon but higher light level. Which can also be infused for 5000 glimmer. A good way to infuse weapons is to buy an exotic weapon of that type. Either heavy or primary. Then infuse for 1000 glimmer. My weapons won’t be as high when you buy exotics for infusions but it’s close enough with all my other gear to not make a difference. That being said I only use cores on weapons that I use in game types that have a light advantage. The point is no cores are needed if you use the exact same armor or weapons. Also using exotic duplicates are a great way to upgrade. Hope this helps😎😎😎