Dr.Martinez said:

Quarterly for the first year is convention rather than evidence, and it is defensible for a simple reason: it is roughly the interval over which HbA1c…

That is correct as far as it goes, and here is where it stops going. A defensible baseline is short: HbA1c and fasting glucose, a lipid panel with ApoB if you can get it, ALT and AST, creatinine with eGFR, TSH, ferritin and B12, and a full blood count. That set catches the things that change, the things that explain symptoms, and the things that alter the prescribing decision. Almost everything else on the long circulating lists is either invariant, uninterpretable without a specific question, or an incidental finding waiting to cause an unnecessary workup.

Dr.Martinez said:

Quarterly for the first year is convention rather than evidence, and it is defensible for a simple reason: it is roughly the interval over which HbA1c…

This is where I part company with the consensus forming above. I would drop the "get everything" instinct further than this thread does. Every extra test is another chance at a false positive, and incidental findings have their own cost in scans, biopsies and worry.

This one has a reasonably settled answer, so here it is. The single most useful discipline is bringing the whole panel to a clinician rather than one flagged value. One out-of-range result in isolation generates anxiety and unnecessary tests; the same result next to the trend and the rest of the panel usually generates a shrug.

LipidDoc_ATL said:

A defensible baseline is short: HbA1c and fasting glucose, a lipid panel with ApoB if you can get it, ALT and AST, creatinine with eGFR, TSH, ferritin…

This is my experience too, for whatever a second data point is worth. Nothing to add that would improve it.