Six years ago I relocated from North Carolina to San Francisco. The majority of my good friends still live in NC, which means a few times a year I end up visiting for at least a week at a time, sometimes longer. The first few of those lengthy trips brought up a dilemma: what do I do about things like shampoo and toothpaste?
Because I'm allergic to my parent's pets/the furry friends they've replaced me with, I always stay with the same friend. Yes, she has things like soap and whatnot I can use and I did for the first few trips, but then I realised a better option: I bought full-size toiletries and left them in the back of the cabinet in her guest bathroom to use the next time I came.
Visiting for a few days and using someone's stuff is totally reasonable. If you're visiting somewhere for a long period of time (I'm here a week this time) and are doing it a few times a year, then you are putting a significant dent in someone's shampoo reserves.
Yes, I could bring it from home, but then I have to check a bag. And my friend doesn't use the same stuff I do, which is fine for a day or two, but when you're talking about a week I start to miss the smell of my favourite body wash and my conditioner's ability to make my hair not look like a complete train wreck. You use some things because they work great for you, which is likely not what your friend or your family uses on the regular.
A few years ago I hit the supermarket on a trip and just bought a full size of everything I use at home regularly. It was maybe a $30 investment and included toothpaste, mouthwash, shampoo and conditioner, a razor and a bonus toothbrush.
I talked to my friend before I did it (don't leave random soap in your friend's house without an explanation) used it for the week I was visiting and then shoved it under the sink when I left. The next time I came I didn't even have to pack a toothbrush, I knew it was all here waiting.
I think we're probably three years into this arrangement and it's always sort of comforting to know I have my own things here. I don't have to make any last minute trips to the drug store because I forgot something and she doesn't feel like she needs to gather anything for me when I get here, I've got it covered.
It's something I'm not sure I would have ever considered doing before, but it's made travelling home a lot easier since I have. If you're spending a long weekend with family this weekend go ahead and intentionally leave your toiletries behind. When it comes time for another trip in a few month you'll be happy you did.