In regards to Frank Leavers’s article about working for a third party after having retired, I think the following applies here in Spain to people who are interested in doing so:
They automatically lose 50% of their state pension, whatever hours they choose or are given to work.
Any taxes or charges paid to the state, generally 2% of their salary, are non contributive, in other words their benefits will not have increased when they stop working.
Health care remains the same, so nothing to worry about that.
The main advantage for hiring a pensioner is the employer’s as their social contributions are only 8% of the gross salary paid and not the normal 32%, the employee, in other words the pensioner, having 2% of this amount deducted from their salary, which means that the employer only pays 6%, which is, however way you look at it, a good deal for the employer but not so much for the employee.