A test suite that fails randomly is worse than no test suite, because the team learns to ignore red builds. Most suites get there by testing implementation details — asserting on internal state and class names that change every time someone refactors. I write tests against what a user can actually observe, cover the flows where a bug would cost you money, and leave the rest uncovered on purpose. Coverage percentage is not the goal; catching the regressions that matter is.
Tests that query by role and visible text survive refactors. Tests that reach into React component internals or match generated class names break constantly and teach everyone to distrust the suite. This one distinction accounts for most of the difference between a suite people rely on and one they skip.
Intermittent failures almost always trace to arbitrary waits, shared test data, or an assertion racing an async update. Each has a fix. I would rather spend the time making twenty tests deterministic than let two hundred flaky ones erode the team's willingness to look at CI.
Checkout and payment flows, authentication and anything touching data integrity get thorough coverage. A marketing page that changes weekly does not. Deciding this explicitly, in writing, is what keeps a test suite from becoming a maintenance burden larger than the application.
Cypress is where my depth is and it remains an excellent choice, particularly for its debugging experience. Playwright has real advantages in cross-browser and parallelization. If you already have a suite in one of them, I would keep it rather than migrate for its own sake.
I do not target a percentage. A suite at forty percent covering every checkout path is worth far more than eighty percent achieved by testing getters. I would rather agree with you on which flows must never break and cover those properly.
Yes, and it is a common request. I triage which tests fail intermittently, trace each to its cause, and fix the underlying race or shared-state problem. Tests that test nothing useful get deleted rather than repaired.