To work as a pensioner the person can only work one or two days a week without penalty
But to work requires some financial outlay in suitable clothing, transport, meals etc so it is simply not worth the trouble
To work full time the outlay and the losses still make it doubtful if it is worth it economically and if the body can cope as most pensioners can only cope with 2 or 3 days a week or 4 hours a day
The penalty limit in this day and age should be least twice of what it is set
