wei_SG said:

The single most useful discipline is bringing the whole panel to a clinician rather than one flagged value.

wei_SG has the substance of this right. The condition it depends on is worth stating. 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 becomes informative again, since it reflects about three months of glycaemia. After the first year, and once doses are stable, annual is reasonable unless something specific is being followed.

wei_SG said:

The single most useful discipline is bringing the whole panel to a clinician rather than one flagged value.

I read this differently from wei_SG, on substance rather than tone. 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.

If somebody has the primary source to hand I would rather cite it than paraphrase it.

Short answer first, then the reasoning. 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.

BethLabQueen 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 my experience too, for whatever a second data point is worth.