When traveling, especially on airplanes, I think (HOPE) we all know by now to ALWAYS put liquid items in baggies in case they open (due to pressurization), or leak. The TSA requires your liquids to be in a baggie and taken out of your carry on luggage, when going thru security, but you should also keep those items in baggies, for checked bags, as well-- for above listed reasons.
I have learned to take the baggie protection to an even more secure level. Even though your liquids are contained in a baggie and generally safe from leaking out of baggie onto your other items....this does not mean that one or more of your liquid items won't leak into baggie and leave a soapy mess on your other liquids and also just make a mess in the baggie to the point it that you just don't even want to try to clean out the baggie for re use.
When I travel over seas, MOST of the hotels have slender bags for 'sanitary needs disposal' I now steal all of them and use them to INDIVIDUALLY put my liquids in and thus separating them from each other, inside the protective baggie. I know this sounds like a complicated explanation....I am not fully awake, so I apologize, but I have some pictures to assist.
To the right you see the bag....now...
IN this picture you see all items in their individual baggie, within the baggie....and thus if one item decides to make a mess the mess is kept to themselves and does not affect the overall happiness of the baggie, or the other items :-)