Although I've only been researching for 3 years, I find that the amount of information available is increasing all the time. I put unknown as the wives' surname, but I also put in any stray bits of data - where and when census forms say she was born, for example - then every now and then I have another try at finding the record of the husband's marriage. Parish records are being added to the internet all the time.

I also check the actual census forms, I've found several visiting relations who hadn't been included in the transcription, and this gives an extra line of investigation.