Spend on the part you remember.

Separate the trip into three layers: fixed transport and accommodation, daily life, and a reserve for changes. That makes the trade-offs visible without turning travel into a spreadsheet exercise.

Protect the reserve

Keep it for changed transport, an extra night or a practical problem—not for filling every empty hour.

Spend where the place is

A central room, a slower train or an extra day can carry more value than another attraction added out of habit.