Ironically for those "people," the opposite is true. The new plastic was outgassing yucky stuff, and the old plastic is less toxic once the outgassing subsides.
On the other hand, ultraviolet light and exposure to volatile hydrocarbons will break down the hydrocarbons in the plastic, making yucky stuff.
Either way, the exposure is much less than that you get from automobiles, power plants, and industries.
So, the answer is to re-use bottles several times, but after a bottle starts to age, for example after a few months, we should send it off to a recycler. Don't be sad to say goodbye to this good friend; plastics weren't made to last forever.
Thus, we can get 10-50 uses out of a bottle that most people would just use once, making our investment in the bottle much more worth it.