Your Welby clock must be repaired. The clock must not change rate from day to day.

The fault is typical of a clock badly in need of cleaning, proper lubrication and possible repair.

For 8-day running clocks, wind the spring enough for 7 days running with no change in rate during the 7 days. For 30 hour running clocks, wind enough for 24 good running hours. It may not be needed to wind tight.

Some old clocks have a mechanism to stop the user from winding too much.