You watch something, you like it enough to want more from whoever made it, and you type their name into the search box. The app returns four films. You watch those and assume you are done.
You are not done. The app returned the intersection of that director's work and that service's catalogue, which for most directors is a small and arbitrary slice. Nothing in the interface tells you what is missing, which is the problem.
Work from the outside in
The order matters. Get the complete list first, then find each film. Doing it the other way round means you never learn what you did not see.
Step one: a full filmography. Wikipedia and The Movie Database both keep complete director filmographies with years, and either gives you the list in one page. Copy it somewhere you can tick things off. This takes two minutes and is the whole trick.
Step two: sort by what you want. A chronological run is the most rewarding approach for a director whose style changed, because you watch the changes happen rather than reading about them. For someone who wants the strongest work first, an ordering by reputation gets you there faster. Neither is wrong.
Step three: find each film individually. This is where it gets tedious, and where knowing the four places to look saves the most time.
The four places, in order
A cross-service search. JustWatch indexes what is currently streaming, renting and selling across services in your country, and checking a title there before opening four apps saves the most time of anything in this list. Treat it as a starting point rather than gospel: catalogues move faster than any index tracks them.
Your subscriptions. Search the title, not the director. A title search finds films that a director search misses, because the metadata on individual titles is more reliable than the people index.
The free ad-supported services. Tubi in particular has a genuinely deep back catalogue of exactly the kind of older studio film that subscription services have dropped. If a film from the 1970s through the 1990s is not on a paid service, this is the most likely place for it. We cover what each free service is actually good at separately.
Your library. Kanopy carries the Criterion Collection and a substantial run of foreign language and documentary work, which makes it the single best source for the arthouse end of most filmographies. It is free with a library card, and the borrowing allowance is set by your own library rather than nationally.
Digital rental. For anything the first three do not have, a rental is usually a few dollars, and for one or two gaps in a filmography that is cheaper than another month of a subscription.
What to do about the ones that are nowhere
Some films are genuinely unavailable to stream in your country. This is not an oversight and it is not something a better search will solve. Rights are sold territory by territory and for fixed terms, and a film whose streaming term has lapsed sits unavailable until someone buys it again. The same contractual machinery decides where a new film goes after cinemas, and it is why availability differs so sharply between countries.
For those, the options are a physical disc, a library's physical collection, which is often better stocked than its digital one, or waiting.
The entries a filmography search misses
Two categories fall through routinely.
Short films and television episodes are often omitted from the main list on a database entry, or filed under a separate heading further down the page. For directors who worked in television between features, that can be a substantial part of the career.
Anthology films, where several directors each contributed a segment, are usually credited to the anthology rather than appearing in each director's list. Worth checking if a filmography seems to have a gap in a particular year.
A note on the search boxes themselves
Searching a director's name works far better on some services than others, and the difference is metadata quality rather than catalogue size. Some services index cast and crew properly and some barely index directors at all.
So a name search returning nothing does not mean the film is absent. Search the title. This is the most common reason people conclude a service does not have something it does have, and it costs nothing to check the other way.
The same habit applies to a claim a film makes about itself. When a film says it is based on a true story, the record is usually public: we pulled the Justice Department file behind one.
