How much time to allocate for specific sites and travel between sites in Paris

To calculate time between points I use CityMapper app and choose either Public Transit or walking. I find they are fairly accurate.

More later on how long it takes “me” through some of your listed museums.

Ruth,
The time I spent at the following locations represents my particular likes, this doesn't include time waiting in line. At some locations, even with timed entries, you would want to add 15-30 minutes to these times. I will note what those are.
Rodin Museum/gardens...2-4 hours
Ste. Chappelle...1 1/2-2 hours, depending on the crowds which slow one down. This place add time to because going through the security is very slow, so 2-2 1/2 hours
Opera Garnier...2 hour,s but I would try to take the tour, so more time with that
Orsay...3-4 hours, depending on your likes (and back and leg discomfort)...I would spend 1 hour on the 5th floor alone
Cluny museum...3 hours (that is me...2 hours minimum for sure)
Luxembourg Gardens...2 hours, because I would use this time to rest and to eat some lunch taken out from somewhere. Otherwise one hour. Though charming, the Luxembourg Gardens aren't of great interest to me.

I have to stop and sit when going through museums. I find that moving from an artifact/painting to another is harder on my back than straight-up walking, fast or slow, so I often need to sit and that means I may take longer than others to visit a place. And some of my times are decided by my preference for a place (I love the Cluny, Rodin, Ste. Chappelle), and by the fact that I may have been there often.
The other places I haven't been to or haven't visited in the same way (e.g. I haven't climbed up the Arc de Triomphe).
As far as going from place to place, I do try to combine sights by neighborhood or route. (Eiffel Tower, Invalides, Rodin Museum, Point Alexandre III make a good day's loop...a full day in my world). I won't discuss time as I walk slower than some. (At 82 and with a troublesome back I will stop every so often to ease the discomfort.)

You have so many exciting things to decide among. Have fun!

Thank you, Pam — I forgot I had CityMapper on my phone from our last European adventure! Super helpful and it looks as though almost everything (one exception) will be easy to navigate with time to spare on my daily agenda. I’m eager to hear how long you usually spend at the various places. We find we always need longer than Rick recommends in most museums, but don’t tend to linger especially long in churches.

Thank you Judy — super helpful, especially the extra context about your preferred way to experience museums. I’m trying to balance seeing as many of the places on my list as possible with not moving so quickly we can’t stop and enjoy just being there!

"We find we always need longer than Rick recommends in most museums,"

Oh gosh, yes. Me too.

I pretty much agree with Judy's time frames. And I also agree the "museum shuffle" is harder on me than flat out walking.

Cluny - if it's not busy, I like to sit in the room with the Lady and the Unicorn tapestries and skooch (technical museum term, hahaha) around the rectangular bench so I can spend time in front of each one.

Concergerie - Maybe an hour or so? Bathrooms are in the far right corner, hahaha! I HAVE taken longer there when they had an interesting exhibition on food and all the explanations were in French, hahha.

Luxembourg Gardens - If it's a pretty day I've spent half a day there sitting either by the Medici Fountain reading or in one of the other areas with seats. Last time I spent a good deal of time searching out the beehives and then the small replica of the Statue of Liberty. There are some beautiful rose gardens if they are your thing and they should be blooming in June. Food nearby - I like both Cafe du Madame which is IN the gardens near the Medici Fountains or across the street-ish to Au Petit Suisse. If you just want to do a walk thru a little of the area then you could send 30 minutes and see some of the lovely areas.

I have not done the Panorama access at the Pantheon, but if you are a Midnight in Paris fan, be sure to pop around kind of behind the Pantheon to the church of Saint-Etienne-du-Mont which is where the character of Gil was picked up in the time-traveling taxi, lol. Plus there is a gorgeous carved double helix rood screen from about 1530.

Deportation Memorial - I have not done this since before Covid and part of it was closed when I went. I'd say 30 minutes for this. More if you have people you want to specifically remember.

I probably spend less time at the Rodin Museum as I really only like to walk thru the gardens. The only time I go into the house is if it rains, hahaha.

I think you're planning to purchase the Passion Monuments Subscription.

Book the earliest entry time for Sainte-Chapelle (9 am?), show your pass to the Moniter at the security line and you should get moved ahead in the queue, head to the upper chapel first and you should walk in to an almost empty Sainte-Chapelle. I spent about 45 minutes inside on my last visit.

Pantheon and Panorama -a separate entrance for Passion holders. If the weather is good, they will recommend climbing up to the Panorama before visiting the rest of the Pantheon. I spent almost 2 hours from top to bottom.

Arc de Triomphe -head directly to the security line and show your pass. About an hour.

Cluny-about 2½ hours including a break at the cafe while waiting for the Tapestry room to reopen.

Luxembourg Gardens - stopped by or walked through several times every stay.

Rodin -about an hour, but only the gardens.

Orsay -about an hour to revisit the Impressionists. It was a late Sunday morning and the crowds were horrible.

I haven't been to the Deportation Museum, but I did visit the moving Memorial de la Shoah. I left after about 2 hours due to emotional exhaustion.

Regarding the actual Cathedral of Notre Dame, not the Towers, my experience last spring was enter as early in the morning as you can. The difference in crowds and noise between 9 am and 10 am was huge.

Also, allow extra walking time between sights. You never know when a pastry window or a welcome seat at a cafe will entice you.

And don't overlook the buses. It saves climbing metro stairs and several routes take you past the highlights of Paris.

Thanks everyone, really helpful! And thanks for the reminder to rewatch Midnight in Paris, Pam!