Delay is a legitimate choice and I support it in plenty of patients. What it is not is a neutral one. It is worth knowing what you are trading, so that the decision to wait is actually a decision rather than a postponement.

What usually does not happen

The knee does not suddenly collapse. Arthritis progresses slowly and unevenly, often with long plateaus. The idea that you must operate now or lose the chance is rarely true and should make you suspicious of whoever is saying it.

You are also not using up a limited allocation. The implant clock starts when the implant goes in, so waiting preserves it rather than wasting it. For a younger patient that is a real argument in favour of waiting.

What waiting actually costs

Three things, and they compound. Muscle, because a painful knee is an unused knee and the quadriceps wastes faster than people expect. Alignment, because a knee that is collapsing inward or outward gets progressively more deformed, and a severe deformity is a technically harder operation with a slightly less predictable result. And the rest of you, because limping loads the opposite knee, the hips and the lower back, and because lost cardiovascular fitness after sixty is hard to win back.

Patients who wait several years frequently do well after surgery. They just take longer to get there, because they start from a weaker baseline.

Delay that is well spent

If you are going to wait, use the time. Structured quadriceps and hip strengthening. Weight reduction where relevant, because load through the knee falls by several times each kilogram lost. Proper trials of the non-surgical options rather than one injection and a shrug. Diabetes, blood pressure and dental health sorted, since all three affect surgical risk later.

That version of waiting improves your eventual result. Waiting passively does not.

Signals that the trade has shifted

Night pain that wakes you. Walking distance that keeps shrinking. A knee that is visibly bending out of line. Falls or giving way. Injections that used to work and no longer do. When several of these appear together, waiting has stopped buying you much.

Further reading: https://www.mayurajcc.com/knee-arthritis-guides/when-does-knee-arthritis-need-replacement and https://www.mayurajcc.com/knee-replacement-guides/do-i-need-a-knee-replacement and https://www.mayurajcc.com/knee-replacement-guides/alternatives-to-knee-replacement