One of the biggest ways to lose money while travelling is package spills. Products can be super expensive. So wasting them is a real pain.
Replacing an amazing product can be especially stressful if you're somewhere new and you're not familiar with the stores. You might have to go without something. In the process of finding a replacement, you can waste money on a ton of subpar products. Before you know it, you've spent more than you originally spent on your fav.
There's also the loss of anything in the blast zone. Alongside your other hair products, you also tend to pack stuff like a curling iron. Curling irons are super expensive, so it can be a huge waste of money when they break. Blow dryers are also pretty expensive and can get gunked up. For both of these, getting them wet at all can also be a big ruinner.
Saving grocery bags is a great way to prevent this. Wap each spillable item in a grocery bag and tie them tight. That way if there is a spill, it is contained.
If the product is in a bottle with a "top" (pump, spray head, etc) pinch the bag around the top. Secure it with some type of band. Go over it again with the excess bag and tie it again.
For other products, like a round container, a bag itself is enough. But it there is a lot of bouncing, the product can "go off". While the spill might be contained, it can cause a big mess in the bag. Securing the bag around the top means that the mess will stay in a small space.