Most people who start an English self study course do not fail at English. They fail in the second month, when the novelty has gone, nobody is expecting anything and the app has stopped feeling like progress. The material was rarely the problem. An unguided course hands you the syllabus and the timetable at once and assumes you can run both, which is a management job as much as a language one. Knowing where these courses break is the difference between finishing one and collecting three.
The breakages are predictable, which is the good news.
The first break is feedback. Reading and listening can be self-checked against the answers at the back, but writing and speaking produce output only a person or a very careful rubric can judge. Left unchecked, an error repeats until it stops feeling like an error. Undoing a habit that has hardened takes far longer than learning the form correctly in the first place, which is the strongest argument for putting occasional human contact into an otherwise solo plan.
The second break is level drift. Without a placement check, most learners settle below their real level, because familiar material is comfortable and comprehension feels like learning. English self-study at the right level feels mildly difficult, with a handful of unknown words on a page rather than none. If everything is understood at once, the session was revision.
The third break is the timetable. A course with no fixed sessions has nothing to miss, so nothing signals that you have stopped, and the gap only becomes visible weeks later.
Large institutions publish graded English material, and the British Council is among the best known. A library-style course gives you levelled units, exercises with answers and a consistent house style, which solves the material problem completely and the guidance problem not at all. Comparing a British Council English online self-study route with a tutored one means comparing a syllabus you administer yourself against one somebody else administers for you.
A routine survives a bad week only if it is small enough to do badly. With no teacher and no fixed class time, structure has to come from somewhere else.
Three things decide whether unguided study works: level, routine and feedback.
Up to a point, and further than most people expect for reading and listening. An English online self-study course British Council publishes gives you graded units with answer keys and no tutor, and that carries a motivated learner a long way through grammar and vocabulary. Speaking is where the ceiling sits, because fluency is built by producing language under time pressure while somebody responds.
For input skills it can be. English self-study of that kind supplies structure and level-appropriate material, and for a disciplined learner it removes the main excuse. What it does not supply is correction, or any pressure to produce anything at all.
Long enough to finish one thing. Nobody else marks the end of a solo session, so the end has to be built into it: one unit, one text, one recorded minute. The useful test is whether it ends with something produced: a written paragraph, a spoken minute recorded on your phone, sentences using the structure you just met.
A plateau usually means the input has stopped being difficult. Changing the material is a faster fix than adding effort: unscripted listening instead of graded audio, a text written for native readers, writing somebody else has to understand. If the stall is in speaking, no change of material will move it.