Based on historical precedents, for how long would sanctions against Russia last? [closed]

If Russia invades the Ukraine, the US has promised imposition of:

significant, and unprecedented economic costs

If that happens, and the US follows through with sanctions, how long are those sanctions likely to be imposed for?

To avoid (too much) guesswork, please base an answer on:

1. historical precedent (i.e. where the US has previously imposed sanctions, how long did they last), and
2. (if applicable) factors that may make this situation different that ought to be considered.