Read some older threads on the topic but they're all closed.
So I usually do laundry at least once on a 2-3 week trip. That means using a wash and fold service if I can find one or going to the laundromat.
I end up walking around a lot so I've gotten shirts which are moisture-wicking but found that these synthetic fibers tend to retain the odor more than cotton.
Just returned from a trip to Northern Italy and Switzerland. So after 1-2 weeks in this trip, which featured temperatures of 35 degrees celsius, I had several shirts and socks which needed laundering. My underwear, I hand wash every day in the shower.
I had time to go to a laundromat but got lazy and figured I had enough clean clothes to make it to the end of the trip. But the problem was that the clothes which needed to be laundered had a strong odor in the little closet in the hotel room in Lugano.
There weren't too many laundromats close to the hotel and I wouldn't even imagine what the hotel would charge by the piece for a half dozen T-shirts and socks and some shorts.
So I hand washed 3 shirts in the sink and they dried pretty well -- moisture wicking as advertised. They didn't smell fresh but the stink was mostly gone. Then the next night, I washed 3 more that I had been carrying with me. But I wrung them so much that I had several blisters which popped. I don't think I could have washed and wrung any more.
I got through that trip but now I have another one coming up and though I'm staying in big cities -- Stockholm, Helsinki, Berlin, Copenhagen -- prices are high and the places are not convenient to where I'm staying.
In Helsinki, one place charges €30, but it's almost a half hour each way from the hotel. In Berlin, there is one service which will pick up and deliver but minimum laundry fee is €40 and the pickup and deliver is another €10. There is also a laundromat too, would have to get on the S-bahn but not too far.
I guess I may splurge. I read that if you leave some of the clothes unlaundered long enough, you won't be able to remove the odor. Another suggestion was to get merino wool clothes. I have some but jeans are well over $100 and shirts are $50 and up.
So maybe some of these services aren't too bad. Or pay the hotel €5 or more per piece.