You should find some form of part-time work or regular volunteer work to keep yourself occupied. The first few weeks of doing nothing post-retirement may be a great experience. But after a while, you will likely get bored with so much free time on your hand and nothing to do. It is hard to fill up all that time with a hobby or hobbies. Also, many of your friends won't have time to meet up with your on a daily basis for long periods.
part time jobs sounds good. But funny I was not able to find any. Middle age sinkie man are biased for most pt jobs, except blue collar type e.g. warehouse, delivery, etc