2 guys left worlds favourite at LHR in recent years on early retirement with a bit of a cash incentive. One got bored and got temporary ramp work with a charter company at LGW, the other left and then it was realised nobody knew how he did what he did and he has been brought back on a daily contract basis, presumably so that they can find out how to replace him!
Some guys don't want a sudden break of service and I think a option of reduced hours or days in a final transition year would be a good idea. One reason why people don't survive long after retirement must be because they aren't prepared.
The company loses a vast investment in knowledge and experience when really good guys leave the company retirement or otherwise and more should be done to accomodate guy's who want a run down period. Unfortunately aircraft engineering is woefully managed by well meaning individuals who just bored of wielding spanners and progressive thinking in this direction is a long way off.