Time Piece

It can purge up to two eligible rewards for Gold while the Fates' Whim is active.

Use it when

Use it for a Gold-focused night when unwanted chamber rewards can be converted into planned purchases.

Limit

It is unavailable outside that condition and trades the skipped reward for spending power rather than permanent progress.

If it is absent

Take the chamber reward normally when it advances the build or the current permanent-resource target.

When to replace it

Keep it while its condition supports the current route, then replace it when another keepsake solves a more immediate constraint.