A two-point calibration is adequate when your samples sit close to neutral. The moment your work spans acidic and alkaline ranges, add the third buffer so the slope is anchored on both sides of pH 7.
Temperature correction is not optional. Buffer values are quoted at 25 °C, and a bench at 19 °C shifts them enough to matter at the second decimal place. Use the table printed on the bottle, or let an ATC probe do it for you.
Watch the slope percentage rather than the pass indicator. A meter reporting 92% is technically calibrated and quietly telling you the electrode is ageing. Below 90%, clean and recondition; if it does not recover, replace it before it costs you a data set.
Rinse with deionised water and blot — never wipe — between buffers. Wiping generates a static charge on the glass bulb that can take minutes to settle and makes readings drift for no visible reason.