I travel internationally alot for VACATION. Maybe 4 times a year or more. One issue that has become more and more of an issue is carry-on luggage. In the US, it is nice that no one weighs your bag. I can always pack enough in my bag for a trip.
Once arriving internationally, I often have to take shorter flights on airlines who have ridiculously low carry-on baggage WEIGHT limitations. 10kg, 7kg. My lightest carry-on bag is around 3-4kg empty. Some even include your personal/laptop bag in that limit.

Some "solutions":
1. Find a lighter bag. I'm the type of person that buys a cheap bag with a good pair of wheels and just uses it until it breaks. Usually the airline replaces it. I've seen some that are a little lighter but are vey expensive and I don't think I will ever pay "hundreds" for a bag. I also only like two wheel soft sided bags and it seems like baggage companies are focusing on 4 wheel hard sided bags. Maybe a duffel bag would be lighter but I want something I can roll.
2. Laundry: Hotel laundry is usually prohibitively expensive
3. In-room Self-Laundry: This can sometimes work. This may allow me to half the weight. I've run into some issues though. Many in-room machines in europe/asia are washer/dryer combination units with no exhaust. These dryers can only dry a few articles of clothing and take forever. Some destinations just don't offer this or the room is much much more expensive or in a poor location
4. Laundromat: I've tried this at times. When there is one close to your hotel it's nice, but this is not always the case. Also, you have to sit there and wait for your laundry so it eats into time to actually enjoy your trip
5. Hand wash: Maybe I'm doing it wrong but when I hang dry the clothes (mostly cotton) they get very stiff. I'm also not too sure how well it actually cleans it. It takes a long time to dry as well. I don't dare try this with jeans.
6. Check in bags: This can be costly if you have many flights. There is wasted time and risk of loss/delay which can ruin a trip. Also, sometimes I do an intl-intl self-connect which would be difficult to impossible if I checked my bag.
7. Wear dirty clothes: I've tried this too. In the winter months its not too bad as I don't sweat much. Though I usually have to pack more layers in winter which increases weight. In summer months, my clothes get sweaty so I really don't want to wear again.
8. Just chance it: Sure, it is rare for them to actually weight your bag, especially if you can skip the check in counter but it only takes one time where someone at the gate catches you and makes you pay or ruins your trip.

Is there anything you're doing that I haven't listed above that works for you?