If you're only looking at your positions on two days:Quote from optionable:
Personally, I have never found greeks useful. I use verticle credit spreads and sometimes ratio credit spreads to trade the futures market.
1) the date you open them,
2) the date they expire...
The Greeks aren't useful to you. They really don't matter.
The Greeks are only useful if you're trying to understand (and of course compensate/hedge) how your position value changes from day to day.