abbreviations - Should "days" be abbreviated when in the context of other abbreviated words?

When writing "1 week 3 days," if week is abbreviated to wk., should days also be abbreviated? If so, what should it be abbreviated to?

Answer

The abbreviation for day is "d".

2wk 3d

This abbreviation is rarely used, however is considered acceptable in certain contexts, one being when used in conjunction with other time abbreviations.