Is the Prio Waterproof?

It’s not. But the breathable mesh upper should help it dry quickly if you get them wet.

How do I care for my Lenas?

You can wash them with a mild soap and water mixture. The canvas is quite durable, and should come clean easily with a little scrubbing. DO NOT place your Lena in the dryer when you are finished cleaning, let them air dry.

Why do my Lenas suddenly feel looser?

The canvas upper of the Lena can stretch a little bit. Most people find this more comfortable as it happens. You should be able to adjust the lacing to feel snug around your midfoot and let your toes be free.