Is 5 days too many?

5 days is absolutely not too many. There is so much to see and do in Amsterdam, plus the Netherlands is a small enough country that there are many easy day trips. You could stay a lot longer than 5 days and not run out of joy.

Dang, I've been to Amsterdam eight times and still haven't even been to the Van Gogh Museum. There is a lot to do.

Just had six days in Amsterdam and 3 in Delft. Absolutely not too much time if only because you can easily venture out from Amsterdam to many other unique places in the Netherlands.

We really enjoyed the Kimpton de Witt hotel, so I'd recommend that, but it seems there are plenty of good hotels in the city. A great perk from the de Witt was the hotel bikes. Sure, we could rent bikes (we did in Delft), but having them at our disposal for "free" was a great bonus. Check with your hotel if they have bikes.
And heed the advice of others to PLAN AHEAD and get your museum tickets when you start finalizing your trip. Sept might be a little less busy, but I wouldn't risk it if you really want to see certain museums.

Having said that, though, if you're looking to check out more places, there are easily 25-30 great Dutch towns and cities within an hour of Central Station.

Add me to the chorus of "no, that's not too many days."

We did 5 days in Amsterdam and that barely felt like enough time to scratch the surface. Amsterdam is, in my experience, one of those cities that reveals more and more of itself as you're there. The longer you're there, the more you discover things you didn't even know were options. Among places I've been, it's probably the city where locals were most forthcoming with recommendations (and good ones, at that). When in doubt, ask an Amsterdammer.

And eat the appeltaart.

Also agree, 5 days is not too much. Our last trip there we stayed 9 days and still have places to see. Going back next May for 5 nights, this time staying in Rotterdam. Enjoy.

5 days is about right or a bit short

Thank you for this. We have 6 nights in Amsterdam in early October and I was worried it was going to be too much.

We really like the Highlander Hotel.
They have a great breakfast