This subject is something of a hobby horse of mine. You should avoid using ED meds recreationally if you do not need them. I know this isn't always easy in the punting world as you may be paying a lot of hard earned etc, but the psychological dependence can be huge.
I experimented with them circa 15 years ago. The strength and durations of the erections was awesome, but the psychological dependence became an issue. I also had many of the common side effects (see below). It took me some time to kick their use into touch.
Their use in civvy world in young people is especially worrying but hardly surprising, given the ease of access to a product which is both highly effective and cheap as a recreational drug.
Not sure if this is true or not, but I have heard that women can often tell (apart from the obvious) whether someone has popped an ED tablet. The face becomes a lot more flushed than normal apparently.
Maybe not all women? ... but an experienced SP will often spot the signs, although flushing isn't always present and if it is, it may not necessarily be due to ED meds but simply anxiety/nervousness/exertion.
With many users, though not all, it can produce problems with struggling to reach orgasm. I had real issues with this when I was using it years ago and even back then, when its use was less widespread, many wgs picked up on this and asked "have you taken Viagra"?