What happens in each zone, by bucket
Buffer
Bridge
Retire
Strong buy≤0.5×
Cash→BTC
(all above floor)
VOO→BTC
(max)
Cash & VOO→FBTC
(max)
Buy0.5–1.0×
Cash→BTC
VOO→BTC
(light)
Cash & VOO→FBTC
(light)
Hold1.0–1.4×
Park excess
→ stables
Hold
Hold
(idle cash→VOO)
Sell1.4–1.9×
Park excess
→ stables
Trim BTC→cash
taxable †
Trim FBTC→VOO
(tax-free) †
Strong sell≥1.9×
Park excess
→ stables
Trim BTC→cash
taxable †
Trim FBTC→cash †
† Selling is gated by FIRE proximity — you stay fully accumulated until ~70% of your FIRE number, then it ramps to full at the target (backtested to protect long-run growth). Bands are fixed × fair value.