When expressing a quantity, do the non-significant figures determine whether you round up the last significant figure?
The international standard ISO 80000 Quantities and units – Part 1: General includes the normative Annex B Rounding of numbers, which stipulates:

Rounding in more than one stage (…) may lead to errors. Therefore, the rounding shall always be carried out in only one step.
Example: 12.254 should be rounded to 12.3 and not first to 12.25 and then to 12.2.

(Note that, in the given example, the ISO standard follows the round half to even rule in which the even multiple is selected as the rounded number. This is the default rounding mode for floating-point computation. Anyway, the rule “rounding shall always be carried out in only one step” is independent of the used tie-breaking rule.)