Incontinence

Have a look at this thread from 2017
https://community.ricksteves.com/travel-forum/italy/incontience-poise-pads
Have a fabulous trip.

I am guessing that European bladders are subject to the same challenges as American bladders. I haven't looked for them, but I am pretty confident that they are available.

Yes, of course they are widely available...just the same as diapers are available for European babies just like USA babies.

Almost everything you buy normally here is available there.

We may be reasonably confident that a certain product is available, but we often don't know where to find it. For example, at home I buy aspirin at the grocery store. In some European countries, it's found in pharmacies.

There's not a lot of time for trying different types of stores when on a tour, or when traveling in general. Some specifics on where to find the items, and what they are called in each country, would help the OP.

I don’t know the specifics of designs, but she may want to bring half of the quantity needed in a lightweight, collapsible zipper bag to give her plenty of time to find a replenishment supply. The empty bag could just be placed inside her suitcase for the return home.

During the RS tour, you may leave a bag or suitcase in the lower storage overnight, so you wouldn’t need to carry it to every hotel if she just wanted to replenish the supply in her suitcase.

A few thoughts...
First, start with a pharmacy and bring one of the pads with you to show. You won’t believe how helpful European pharmacies are, even with a language barrier.

Second, speak with your guide and let them know your needs, they will probably arrange a time to go with you to the pharmacy.

I have seen these items in pharmacies in France and Italy. When I googled incontinence Germany just now, a variety of online products came up...even without knowing German, you can check if any of the pictures look like what your wife uses.

Don’t worry you will find them! Maybe even a style your wife will like better than what she currently uses. Have a great trip!

Fill a small dedicated backpack with enough supplies for your travel dates. Finding appropriate shops to buy them may be a problem.

I need to use some small pads for bladder leaks, but not the full incontinence pads. I took enough for my trip. While bulky they are easily squished in a compression bag to take up less room in my bag. I would take as many as she can fit into her bag and if running low on the tour ask the guide for assistance in finding a suitable store to buy some, even if they aren't her preferred brand they should be comparable. Europeans have the same issues in that area that we do and supplies shouldn't be that hard to find.

These and hearing aid batteries have been a bit of a challenge on our trips. I’ve given up on the batteries as they are so small and easy to pack. Pads have been available in large cities. We always bring about a weeks worth. We also bring a collapsible bag. When we see what we need we buy enough for the rest of the trip and that bag comes in handy.

"If you let us know which countries you will be visiting locals can give you more specific advice."

OP mentioned they are doing Rick's 21 Day Best of Europe tour.

https://www.ricksteves.com/tours/europe/europe-21-days

2 nights - Haarlem
2 nights - Bacharach
1 night - Rothenburg ob der Tauber
2 nights -Reutte
2 nights - Venice
2 nights - Florence
2 nights - Rome
2 nights - Cinque Terre
2 nights - Lauterbrunnen Valley
1 night - Beaune
2 nights - Paris

To me, the places where it would be hard to get to a pharmacy so I'd want to stock up ahead are:

Rothenburg - just one afternoon and evening here and I found a lot to see, although you are right in the center of town so a pharmacy would be available
Reutte - The hotel my 2014 tour stayed in was in kind of a residential area so would have been a mile or so to the City Center to find a pharmacy.
Lauterbrunnen Valley - My tour stayed in Stechelberg. Some still stay there I think and some stay up in Muerren. There is NOTHING in Stechelberg except jaw-dropping views. The closest pharmacy would be a bus ride away in Lauterbrunnen so by all means have enough product to get you thru this stop.

I'd also check to see where your Sundays fall. I believe there are always a few pharmacies open on Sundays and if you can find what you need in a larger grocery store there may be some open on Sundays. By and large I think fewer things are open Sundays in Europe than one might expect in the US.

This is a fun and wonderful tour!

No pharmacy in Lauterbrunnen, IIRC. There is the Co-op grocery store with a limited if quirky selection of products there. (Commercial hedgehog food, yes, but probably not bladder pads) There's a pharmacy in Wengen but I suspect skews more toward sports medicine needs. If you need to resupply in Bernese Oberland, Interlaken is probably your best bet.

I think I would stock up in Haarlem or Amsterdam, and put them in "deep storage" on the bus. The drivers are great about letting you access things you need. If she just needs pads, carrying a few days supply in regular luggage or bus bags shouldn't be a problem. If she needs the briefs, they take up a lot more room. But stashing a couple of 24-packs in deep storage would work. You can replenish in Florence, Rome, and Paris. Your guide will help, as well.

I would suggest ordering on amazon.co.uk and have them delivered to one of the hotels en route.

Easy to set up account and can be delivered for your arrival.

Check here they have a wide range of incontinence pads I also shop from here.
https://www.incontinenceproductsdirect.com.au