Visual design Theory: The design of validity time format

Recently designed a coupon list, there is a valid date, because the space is limited, you have to put the start date and end date on one line, so that there is a row of numbers, dates are several of our accustomed format, which is better?

On the pictorial words:

Although only a small period of validity, but a list of different ways of presentation, can help us find the best solution;

Usually our design is the same, often do a program, because spent a lot of energy, always unconsciously think it is good enough, when we put down the baggage, listen to other colleagues ' suggestions, may see a lot of their own not thoughtful details have yet to be optimized, optimization and the first edition to compare, is it better?

I believe in good visual design, the details can withstand scrutiny.