English proficiency varies enormously between countries, so the useful skill is reading the signals for your specific destination. Broad patterns: northern Europe, Singapore, and countries with English as an official or administrative language are effortless. Major tourist cities worldwide function in English within the tourism layer, hotels, attractions, airports, even where the general population speaks little. The gap opens in everyday errands: pharmacies, local markets, bus drivers, and government offices are where English thins out fastest, even in otherwise easy cities.
Age and profession matter more than geography sometimes: younger people and anyone in tourism or tech usually manage, while older generations and rural areas often do not. Countries whose media dubs foreign films tend toward lower everyday English than subtitle countries, a surprisingly reliable pattern.
For daily tasks, visitors nearly always manage with a combination of English, translation apps that work offline, and patience, and locals worldwide respond warmly to even a few words attempted in their language. Check recent traveler reports for your destination, and if you are headed somewhere with genuinely low English, download the offline language pack for your translation app before you land. That one preparation covers most of the gap.