hotel reservations essential?

A better question might be to yourselves..."Will it throw a wrench in my plans if I arrive at a destination and there are no rooms, or no rooms that I can afford"? If the answer is no - then you have your own answer.

8 cities in 10 days? That I would not try, but I have traveled without booking lodging in advance for every night.

It is possible to find last-minute lodging, you need to be flexible regarding cost and location and facilities. We have done it in July when it rained in Switzerland and we drove to Italy instead. While it is stressful and tiring to drive into a town & then find lodging, it can be done and increases flexibility.
I would not try it if traveling by train.

Enjoy the planning and the trip!

It depends.

For my nerves I always have reservations for the weekends or any special places I want/need to stay (ie Gasthaus Aescher). Nothing ruins a day, or a relationship (such as a marriage) faster than looking for a bed late into the night. In Switzerland 'late into the night' can literally mean 8:00.

Also, that is a very ambitious plan. I would put it all on a map and whittle it down. I like to add in 'travel days' between each destination.

linda,

September can be very busy in Europe and in the areas you're visiting. You could arrive in a particular town and find that some sort of local festival is in progress and hotel rooms are in short supply. You'll waste valuable holiday time looking for accommodations or may have to accept something at a higher price, in a dodgy area or at a lower "comfort level" than you're used to.

I'm not sure you're going to be able to get to all the places on your itinerary. Visiting eight locations in ~ten days is going to be "challenging" (to say the least). That's an average of about 1.3 days per location, with no allowances for travel times between them which in some cases may be lengthy. I'd suggest paring the list back, as with your present plans you'll be seeing more of Switzerland through the windows of your conveyance.

Thanks everyone for the comments. We are not going to 8 places in 10 days. More like 6 places in 10 days. Not spending night in Zurich, planning to go directly from airport to Appenzell. Also Milan is not included in this time period. Will spend extra 2 to 3 nights in Milan. I am loosely basing our tour on RS 2 week train tour, but cut out some of his destinations. In light of your comments, we might drop Lugano. Or simply stop there or the closest city to the southern Italian border (using Swiss pass) and buy a train ticket to Milan.

In another post, I had read that there are travel desks at most major train stations that can help find last minute hotels. Any experience in September? Do most Swiss hotels have strict cancellation policies? Thanks.

There are many, many tourists offices in Switzerland.

My limited experience: (around Sept 9)

We used one several years ago in Luzern, at the train station, to find a last minute hotel. We ended up at a place so bad we had to double-sheet the bed for our 3 year-old because of concern over bugs, there was a crack in the ceiling corner where the walls and ceiling met that was completely open and covered by an umbrella, the shared toilet was filthiest than one found at a late-night New Orleans dive bar, and 'stuff' suck on the floor and table that had survived so long it was now part of the floor and the table.

The tourist office recommended it as a good place for a family. We termed it later the 'Lowsy Lion'. I have traveled, including hostels in downtown Amsterdam, and have never stayed at anything like it. We should have known when they were cooking something on a hot plate behind the 'check-in' counter. But it was late, it had been long journey, and we were tired.

Just be aware of what your options are going to be the day and time that you plan to arrive. They could narrow significantly from today until then.

I'll jump in on this one...
My husband and I used to travel all summer in Europe with no reservations. Our experience was mixed when having tourist offices make arrangements for us. We did have the experience of arriving in a town where there were literally no rooms available or rooms available but we couldn't afford them. When that happens iit can eat up all of the time left in your day because you have too either find another town in which to stay or drive around looking for something at a place that isn't registered with the tourist office. If you have loads of time it's OK but you don't have loads of time with the schedule you have planned.
When there were rooms available sometimes they were OK and sometimes they were pretty atrocious. You can't be picky and you have to be prepared to take what's available.
The other thing I will add is that with your tight travel schedule you will eat up a lot of time every day making arrangements for lodging that you could have easily taken care of before you left home. With your itinerary there really is no flexibility In your schedule and therefore, no advantage to be had in waiting until you arrive to find lodging.
Maybe you have the idea that you'll pull into town and you'll see the perfect little place and you can just pull in and they'll have a room? That isn't realistic and it rarely happens that way - believe me!
Save yourself the stress of uncertainty and just make reservations before you leave home.