How often

Once, carefully, is enough. A figure taken with the method recorded and an uncertainty attached does not go stale the way a weight or a blood pressure reading does. Remeasuring next week does not update it; it just samples the same distribution again.

What remeasuring actually gives you

Take the same measurement twice in a week, following the standard method both times, and the two numbers will not match exactly. That difference is not change. It is the ordinary spread you get from small variations in pressure, angle, and erection state - the kind of thing measurement error already accounts for. A figure taken with three readings and a stated range, something like a value plus or minus a few millimetres, already contains this spread. Measuring again inside that range does not sharpen the figure. It just adds another point that was always going to fall somewhere near the first.

The only thing repeat measurement over weeks or months actually demonstrates, reliably, is how much noise your technique produces. That is a useful thing to know once - it is roughly how the within-session and between-session split gets established - but it is not a reason to keep doing it. Bland and Altman (1986) frame repeatability exactly this way: a property of the method, estimated from repeated readings, not a series of new results.

Why the frequency question comes up

People ask this question expecting one of two answers: a maintenance schedule, or reassurance that checking again will show something different. Neither is what the method supports. This site describes technique and published data. It has nothing to say about whether a number can change, and does not imply that it can - that claim belongs to a different, and much less careful, part of the internet.

If what is actually being sought is not a repeat figure but a repeat judgement - has an impression of a photograph shifted, has a rating moved - that is a separate question with a separate instrument. A photo-rating score can genuinely drift between submissions, because it depends on the photograph and the audience rather than on a fixed protocol, which is not true of a bone-pressed reading. An AI scoring tool evaluates a photograph against a rubric each time it is asked, which is a different exercise from measuring a shaft with a ruler, and how consistent that kind of repeated scoring is is a question for the service that runs it, not for a tape measure. A human reviewer's opinion can shift between two viewings of the same photograph too, for reasons that have nothing to do with anatomy - that variability is something Rate Penis is upfront about - which is one more reason to keep a measurement and a judgement in separate boxes.

When remeasuring is worth doing

There are legitimate reasons to take a fresh reading: the first one was rushed, the method was not recorded, or a different instrument is being tried to check the first result. Checking one instrument against another on the same object is a genuinely useful exercise, because it isolates instrument error from technique error rather than just adding a data point. Outside of that, once a figure exists with its method and its uncertainty written down, it has done its job.

A number does not need a schedule

Compare this to how published data is used: a study measures a large sample once, under a fixed protocol, and the resulting mean and standard deviation stand as a reference indefinitely, not because nothing varies within the sample but because the figure was never meant to be a running total. Even population references are revised rather than tracked: Belladelli et al. (2023), pooling 75 studies of 55,761 men published between 1942 and 2021, reported that mean erect length in the published studies rose over the past three decades - a difference between study populations, not a change in any one man. A single self-measurement works the same way. It is a snapshot with error bars, not a metric to watch trend lines on.

If the interest is in tracking something over time, the honest question is what, exactly, is expected to move, and on this subject the answer from the literature is nothing worth checking for. A rating on a site like Rate Cock can change between submissions because the judgement is subjective and the inputs - the photograph, the angle, the audience - vary each time. A bone-pressed length taken correctly does not have that kind of freedom to move, which is exactly why remeasuring it rarely tells you anything the first careful reading did not.