This one might seem odd to some, but I have found it very helpful. I travel with my own bar of bath soap. I have found that the bath soaps can be very hit or miss when traveling. Some of them can be very powerfully scented, and often times with an unpleasant fragrance. Other soaps are so small that they are difficult to hold on to. The worst is when one is allergic to the soap that is provided. Some times there is no soap at all in the hotel bathroom. Don’t ask me about the last two, I just know about them.
Traveling with my own full size bar of soap, it is even allowed in a carryon, has solved much of these issues. It has been more pleasant than I expected. I am sure that other travelers will also travel with their own hair care and other products, but I don’t have enough hair for that to be an issue.