If you are new to crafting, this is pretty much the only time in the game where it makes sense to level your gear fairly evenly rather than do 1 piece at a time to max level. As you increase levels, upgrades cost exponentially increasing amounts of shards but pay out the same buff %.
First 2 tables are for gear information (buffs and costs) and the last table is the important one which analyzes the data to show which ones are the best to go for first. As a rule of thumb, always get a full set of gear before spending your shards to upgrade 1 piece, and upgrade your pieces going lowest # shown first.
All information found in mech’s spreadsheet vault