Set a 60/40 split and ignore it for ten years? Winners grow faster, so the mix quietly becomes 78/22. See the drift, the trigger and the fix.
Your target becomes fiction fast. See the real split after doing nothing for years.
Know exactly when the mix strays far enough to justify the trade.
New money is the cheapest way to rebalance — add to the lagging asset instead of selling.
All calculations run locally in your browser. Nothing is sent anywhere.
Keep risk where you planned it.