Subway ticket valadation

The pass is validated once only . As was explained to me when I purchased one , any subsequent validations will invalidate the pass .

Yes, you validate it just once. That "starts the clock." So, if it's a 7 day pass, validating it determines what Day 1 is, and it is then valid for that day and six days thereafter.

As Steven says, validating it more than once would look like an attempt to "restart the clock" - not allowed. And not validating it would be an attempt to keep it going indefinitely - also not allowed.

That's a great convenience of passes. You buy it and validate it on first use, then it just stays in your wallet, purse, etc. When an inspector comes around, just show the pass; otherwise, you don't have to think about it or do anything, except get on board the bus, tram, U-bahn, etc.

Don’t forget to keep your ticket with you. Over the course of 4 days I was checked 3 times. All occurred just outside of peak travel times.

Support existing answers: One and multiday tickets are only validated / time stamped once.

... or never, if you buy your ticket via the BVG app, wich is a mobil info system too.

Even mobile tickets are validated but done automatically at time of purchase :-)

But not with the 4-drives single tickets. There you have to validate the remaining 3 tickets by activation in app.

Thanks for the help!