For my first adventure outside Europe, a trip that covered 18 countries (Asia and Australia), I got not just one but two IDPs. My research told me that there were two conventions and that not all of the countries that I hoped to visit had signed the same one. These got very little use, partly because I did not drive much except in Australia and also because on the few times that I did, no one cared.
That was a very long time ago (early 1980s). I have had not had an IDP since. I have driven in the US, Canada, and quite a few Asian countries since and no one has every asked for one.
As other have said, if you are resident then different rules may apply.
In the 1990s, I lived in Sri Lanka and I needed a local licence. I visited a police station, showed my UK licence, and an officer typed my details onto a pre-printed card. Later again, I lived in the Philippines and again got a local licence. This was a bit more complex; I had to take the theory test but not the practical test. I received a credit card sized photo licence similar to my UK one. The procedure took several hours but did not cost much. Renewal can be slow. Once I needed to give a urine sample and take an eye test. The eye test was not hard; the optician asked: "Do you wear glasses?", I said: "No", she said: "Are you sure?", I said: "Yes" and the test was complete.
There may be other things to watch. Here in the UK when we switched to credit card sized photo licences, we were issued paper counterpart licences. In principle, you needed this when renting or driving abroad. I have been asked for a couple of times in the UK (renting a van and test driving a car and a motorbike) but never abroad. I remember once on holiday in Florida, I noticed that some of the people ahead of me in the queue for the rental cars had these counterparts. I was a bit nervous as I had forgotten mine. Fortunately, I was not asked for it.
These counterparts are now obsolete; they have been replaced with a web service. You should visit this before renting. I did before my last US visit but, of course, I was not asked about it.
DVLA View Driving Licence