The clothes are made to last a few months, for one pregnancy not for daily wear for years like regular clothes.

They should last you through your pregnancy without trouble...and odds are will last through an additional pregnancy.

I will caution you about used maternity clothing. They can work fine BUT they have been stretched out by a previous pregnant mom. The pants will lose their stretch and odds are you will find you are constantly hiking them up in the earlier months of pregnancy because your belly isn't as big as the clothes were stretched! Which, really isn't a big deal but is an issue worth noting!