The biggest target value is not your average
Treble 20 scores 60, the most you can score with one dart. Treble 19 scores 57. If every dart hit the intended treble, 20 would be the obvious scoring target. Real visits include singles and neighbouring sectors, so the better target for your current throw depends on where all of your darts land. A single spectacular visit cannot answer that question.
The neighbours of 20 are 5 and 1; the neighbours of 19 are 7 and 3. A sideways single miss can therefore have a different cost. That does not prove beginners should always aim at 19: your vertical misses, treble hits and comfort at each target also matter. Measure the result instead of choosing a rule that ignores your throw.
Run a fair 20-versus-19 comparison
Warm up without recording a score. Then play ten three-dart visits aimed at T20 and ten aimed at T19. Record every dart, including misses, and keep the same pace. On a second day, reverse the order so that 19 gets the first block. Repeat over several sessions rather than deciding from your best day on either target.
Use separate games in scoring practice, with one player and ten rounds each. Note the intended target beside each result in a notebook: the game does not automatically label an aim-at-19 experiment. Do not use 501 for this comparison, because checkout darts change the task near the end of the leg.
Read the totals without overreading them
Suppose a practice block at 20 produces 412 points from 30 darts, and a block at 19 produces 456 from 30. These are illustrative numbers, not player results. The three-dart averages are 41.2 and 45.6: divide the total by 30 and multiply by three. In that pair of blocks, 19 scored better. It does not establish that 19 will always win.
Combine equal-format sessions and keep the dart counts. If blocks have different lengths, calculate the average from total points and total darts, not from an unweighted average of the session averages. The guide to darts averages explains why. Also note whether the apparent advantage disappears when you reverse the order.
Choose the next target before a bad visit chooses it
One miss into 1 is not a reason to switch immediately. If you change target after every disappointing dart, you never give either target a fair run. During practice, keep the agreed target for the whole block. In a match, you might switch because a dart blocks your view of the treble or because the remaining score calls for another number.
If your main problem is a wide sideways spread, use the grouping drills alongside the scoring comparison. Choosing 19 may improve today’s points without solving the underlying inconsistency. Keep target selection and throw practice as two related decisions rather than treating one as a cure for the other.
Near a checkout, the remainder takes priority
With one dart left on 186, S20 leaves 166, which cannot be finished in three darts. S19 leaves 167, which can. That is a setup decision, not evidence that 19 is the better scoring target overall. Learn the bogey numbers and setup examples so you can recognise when the next visit matters more than one extra point now.
Use your repeated practice results to choose a default scoring target. Keep enough familiarity with other sectors to handle finishes and blocked targets. You do not need to declare lifelong loyalty to 20 or 19; you need a sensible starting choice and a clear reason when you change it.