I have always ever used one toothpaste at a time; mainly because that’s what I grew up doing. You have to first wait for one item to get used up and then you open the next one. Then on a random day sometime last year I asked myself WHY I had to wait till something is finished and thought, there is actually no evidence to support that anything tragic will happen if you do so. And so I started using not just toothpaste but fragrances, shower cream, bath soap, cooking oil, fruit juice; anything really. Life is too short to endure a whole boring tube of Colgate toothpaste that you actually don’t like when you can just use Aquafresh or whichever toothpaste tickles your fancy. Imagine missing out on your other favourite lotion because you are waiting for the other bottle to finish first. Do yourself a favour and use all your favourite things in abundance while you are still alive and well!
Please note this variety theory does not apply to your boyfriend or girlfriend, it will not end well if you look at things from my toothpaste point of view.