it all depends also where u apply and how long it takes to officially change to married status; i'll explain: if u get married u need to update the embassy; now depending on the embassy they will either continue processing u as common-law or they will process u as married and they will ask u to provide the necessary official proofs: official marriage certificate and other documents where u r declared officially as married (some areas in the world do need lots of documents do be updated

); they could put on hold ur application until they get these new documents and in some places (the more bureaucratic and corrupt) it could take up to 6 months...hence the big delay and Baloo's advice...also maybe they will ask u to update ur forms, resubmit them, submit additional proofs (wedding invitations, receipts, photos, etc) and hence other delays...
i think some VO r more iffy from the beginning than others....if urs is not that iffy then just send the application now if u r ready; if not, prepare and send once u r married
i would b curious what others think also