Replacing desktop clock battery

The display of this very old desk clock had been fading rapidly over the last week or so. This morning it completely faded away.

Battery: CR2025. Got the Sony one and the shopkeeper warned me that there are imitation Maxell types in the market. They work but do not last.

Full display contrast achieved with new the new battery.

Question: How long would it last. When will I be back here to check?

Warm day with aircon off.