Probably 300 exotics. Mostly Dupes from my warlock.

Many. Dozens now because I have three Guardians and I've been playing for years. I look for spiky stats and try for at least 65 base stats, although sometimes lesser stats actually work out better depending on how well the piece meshes with others. Lately, because Resilience basically became the premier stat for all Guardians I have actually sharded some of my old armor. If I haven't used it in two seasons it means I've moved on permanently to another piece.

Just counting my Hunter main here, Fatty and Floaty have some mastermorked stuff but nowhere near as many. Hunter. Legenday Armour: 61 pieces. Exotic Armour: 17 pieces. I'm one of those players that actually makes "builds" and over the last few seasons there has been a lot of meta changing (Void Volatile, Solar Scorch etc.) with different Exotics being relevant for different activities (Grandmaster and general endgame, Raid, Crucible) so I've built and masterworked around those exotics per that seasonal fad. My friends and I also try to farm GM's which give a decent amout of Golfballs (Ascendant Shards) and dungeon bosses like Ciaitl for Artifice armour, so I've been using the excess Golfballs to masterwork some of the better armour I've been getting in hope it will be relevant in the future. Better than wasting them or storing too many in postmaster, we know how that works out! It has made me a bit of an armour snob now though, I delete anything under 63 stat total because most of what I have is 66-68 before masterworking. As for building I use 2 external apps for this; the classic Destiny Item Manager which has consistently done a better job of gear management than Bungie ever could and has great armour/build optimisation features, and [url=https://d2armorpicker.com]D2ArmourPicker[/url] which is a build specific tool with a few different options and approach than DIM. I recommend both. One note I'll make to you is about understanding armour stat rolls, the top three stats (Mob, Res, Rec) are grouped together as are the bottom three (Disp, Int, Str). When armour is acquired a stat total is rolled first (ie 64) then divided between the top and bottom groups (eg 32+32 or 33+31) then divided into that groups 3 stats. As such you will never get armour with high stats on all three in one group such as Mob, Res and Rec getting 20-ish each and Disp, Int, Str all getting only 2. Worth remembering when focusing armour. [spoiler]Thats a basic, easy to understand explaination of armour rolls but inaccurate, it actually uses a Plugs system. If you want to know more (and get a headache) then go find the lengthly reddit post.[/spoiler]