Ha! My opinions may not be (scratch that) likely are NOT the same as the average doctor (so take that as you will).
I think people using pre-workout admixtures are looking predominantly for the stimulant effect. So sure...there is an adaptive response process by the body to agents such as these, and your body will become very acclimated requiring higher doses and so on...you've probably heard that before. At the same time, the concern is ... the HOW your body is dealing with this. Cortisol levels become amped and your body becomes subsequently resistant to a lot of things.
Its not the end of the world; I believe stimulants have their place in productivity, performance enhancement - you can usually offset this by NOT taking it on NON-workout days; some products say to take every day. You can also do what I recommend with ANY stimulant product and that is to adopt a 5-on, 2-off ("weekend holiday") protocol OR alternatively, a 3-on, 1-off, etc... protocol making sure things are cycled to offset this "autoregulation."
You might benefit by ingesting some adrenal adaptogen style supplements (i.e. - Rhodiola, Ashwaghanda, etc...) especially on days "off" from the stimulants.
From a health risk standpoint; ahh, that's tricky...see even a little stim may go a long way in someone with an anatomical variation that they are unaware they have. Acute increases in blood pressure could promote long-term hypertension; which would not be good in some cases (especially those using progestin or nandralone species anabolics). So ... maybe, but I wanted to be sure you saw how to avoid it in most cases (cycling) as illustrated above if you are going to use them.
One of the things I want to be very clear about is presenting objective info without too many "recommendations" per se. Recommendations would be much more specific and unique to the person asking the question.