Reloading since 2010, so 16 years.
I have written down EVERYTHING, and just checked... I'm at 73,778 reloads (pistol, rifle, shotgun).
I have reloaded: 223 Rem, 220 Swift, 22 Hi-Power, 243 Win, 250 Savage, 6.5x52, 6.5x55, 270 Win, 7mm WM, 7mm Mauser, 7.5x55, 30 Carbine, 30.06, 300 Savage, 308 Win, 7.62x39, 7.62x45, 7.62,54R, 303 British, 8mm Mauser, 8x56R, 405 Win, 450 Bushmaster, 43 Mauser, 45-70, 577 Snider, 7.62x25, 38 S&W, 38 Special, 357 Mag, 9mm Lugar, 9mm Largo, 10mm, 44 Rem Mag, 45 acp, 45 Colt, 454 Casull, 410 bore shotgun, 12 gauge, 20 gauge. And just ordered dies for 338 Lapua Mag and 7.5x54 French!
Regrets? Like others said stocking up on sales. I started reloading only pistol so when the Dominion powders were "hot" I didn't get any (plus too cheap to pay for shipping). I did get on the primer bandwagon - I believe it was SFRC that had boxes of Remington Primers for $20 or so - I should have bought MORE.
I guess a minor "community" regret is the bad-mouthing of "other" brands. I have dies from Lee, Redding, Lyman, Hornady, CH (and maybe more? i forget) and they all produce ammo good enough for me. Currently own 6 Lee presses but I'm sure other brands would work fine. Most of my reloading is on a Lee 4-hole turret press, with a Lee single stage to resize rifle brass as needed. For 9mm Luger and 38 Special I use a Lee 4-hole progressive (4000?) and have been pleased with it.
YMMV