Install N apps where N is the number of markets you eventually travel to. If you only ever travel to one other market maybe 2 is fine. If you need to download tens or hundreds of apps that might be a bit much. Not everyone will travel to that many markets, but for those who do, they might care.
1) Find out what the required app is
2) Keep them all uptodate
3) Keep your details registered with them, despite using them once every 2 years
4) Remember which app to use in which city
Uber just works. Sadly apart from where I live, which is like the 1990s in terms of taxi provision.