Under tools section in Beersmith Yeast starter
Yeast Starter Settings: (at the bottom/and I am a shaken not stirred kind of guy - no stir plate)
96% Viability with a
20%/month aging rate
Assuming an Ale:
337B cells estimated
1.052 Starter OG
It is your brew but that is I how I approach making a starter. With unreliable, old, prone to stall yeasts, lagers, Belgians, hefes you may run into a less than desired performances out of your yeast. But that's based on my opinion and personal taste. It is always good to have a "relax, have a homebrew" approach. Your beer should be fine either way, you will have a brew.