[RichardLake]

That depends, the dropped unit could be either a year or a month.

[jchw]

You don't drop the unit for months, so it's not ambiguous in context.

[klodolph]

It’s understood in context, that’s the point.

[pzo]

no it's not - it's assumed by maybe taking the most likely unit (year). But if the conversation is in hospital with your kid having emergency I guess doctor would appreciate to know if they will have to do surgery on 3 months child or 3 years kid.