The 10% Rule is really simple: no matter how much you love design, no matter how outsized the ambitions for your design career, always put aside 10% of your life for something else that isn’t design-related.
The 10% Rule
Eric Heiman

This is SO damn true. And I’d say I would save also 20%, not only 10%.
I often see around me people identifying themselves with their job or — worst — with their job title.
Nothing bad to have a passion for one’s own job, it’s more than great and right. I always support the idea that you should have a job that you really really love.

But identify completely with the job, where nothing else matters, where there is no room for -as you also write- experiences, is a nonsense. I totally agree: it’s that 10 or 20% that fuels your creativity.