skill levels DIY learning

How do you test your skills if you are not learning traditionally?

I stumbled upon some good testing resources this week but I am curious as to how you measure your own progress if you are not learning with a tutor or in a classroom?

https://spanish.kwiziq.com/learn/listening

There are lots of tests out there, but I don't take them. I just estimate my level based on how comfortable I feel, and what my tutors say.