Seems like everyone's freaking out over payment terms lately. Abbyg14 has a point about net 30 being the standard, but is waiting an extra month for money really that big of a deal for most jobs? My last freelance gig paid on net 45 and I just planned my bills around it. What kind of work are you doing where 30 days breaks everything?
Have you noticed how everything in this economy is designed to make you wait longer for money but expects payment upfront from you? @johnson.daniel is right that you can plan around it, but the whole system is tilted so businesses and landlords get paid fast while regular people float them for weeks at a time. It's just one more way the little guy absorbs all the risk.