Productivity is a very important matter in the world of the employed. Tote that barge, lift that bale; as the lyrics of the song had it, many years ago.
As a result in the world of work there is a strong focus on, and belief in, measurement; measurement of output, measurement of the effectiveness of an employee. It seems so rational compared with anything as old-fashioned as judgment; and we could have an argument over the merits of measuring versus judging as a way to assess an employee’s worth to a company.
But let’s not do that, and instead consider retirement. As a retired person, you can shuck of any sense of measuring your success, and swim with the tide, as you no longer have a boss.
And now for a practical example: learning a foreign language.
You could take all the exams and get all the certificates that you want and need: all good. But, and this is a CRITICAL difference, you could also simply work to improve your proficiency in your chosen foreign language: that is to slowly immerse yourself in the language and its associated culture. You won’t be able to measure your success, but that is OK, as you can form a judgment. And guess what: your stress levels will reduce because you are not being measured!
This is a radical distinction; as you have moved from measuring to judging your success.
At base, this is all about setting your expectations. The choice is yours. I would simply emphasise that in postwork (as distinct from when you had a boss) you can set your own expectations and work within those; you can even change them of your own volition, without a need to ask anyone for permission.
Retirement: you won’t know what it is like until you get there.