Keep your mind active as much as possible or you will leave yourself muddled. If Stephen Hawking can keep himself going, then it won’t hurt to dabble.
There is so much out there you can choose from. Aside from reading paperback books or writing poems, play some mind games every now and then. You can find quite a few under internet search.
There are also numerous board games out there, from Apples 2 Apples to ZÈRTZ.
Perhaps you think you’ve finished your schooling? Take an adult education class or a workshop and pick something you might want to try.
Even in Heaven, there is no time for sleepyhead. And I will have to keep my arse on rev.