Even if your toiletry kit will be going in your checked luggage, still put all the liquids and gels in spill proof jars and bottles and use a zip lock bag. It is not nice if any of these things end up soiling your clothes.
I like to also use a hanging toiletry bag to use in my destinations shower.
Add or subtract in your toiletry kit to suit your own needs. I would advise not to take full size containers if you are going on vacation for less than a couple of weeks. Even if you are staying longer you can buy most of these products everywhere unless it is something you think will be hard to find and just wouldn't want to be without, like maybe your favorite face cream for example.
Other things you could pack in this bag would be your laundry kit. A clothes line, laundry detergent packets and a small sewing kit.
I refill travel bottles and keep them in my travel closet.
If you travel frequently you might want to do this, as they are always ready to go when you are.
The squeezable, refillable wide mouth Gotoob bottles work really well.
A lot of things can be iliminated if your staying with freinds or don't mind using hotel products. You may want to check ahead because some apartments, hotels, b&b's and especially hostels may not supply products.