Choose an alternative for a specific reason
If a film is missing, look for another catalog or service carrying that title. If a series has an unavailable season, compare the same season elsewhere. If the issue is subtitles, look for a viewing edition with your language. These are different needs and do not always have the same answer.
Start from the movie details
A title’s year and original name help distinguish remakes and similarly named releases. Search that combination on JustWatch in your country, then compare subscriptions, rentals, purchases or free-with-ads offers where listed. An offer for a trailer is not an offer for the complete film.
For continuing television
Keep the series title, season number and episode number together. A service can carry one season without carrying another. The episode guides for The Rookie, Stranger Things and The Summer I Turned Pretty help you identify the chapter before you compare viewing choices.
Using recommendations from Reddit
A discussion can help you discover a title or hear about someone’s experience. Read the date and the country mentioned in the comment. A successful viewing report from a different region or an older post does not establish what will open for you now.
Keep your watchlist portable in practice
My List is a convenient browser-local reminder. For an important long queue, also keep the titles and years in a note of your own. That gives you something useful to search when a website, browser or device changes.