when should i upgrade to sql server?

i'm currently using ultimate survey professional 7 with an access database. i'm about to roll out some surveys to an email list of about 30,000. do you think we should upgrade to sql server at this point? thanks.

[ncushing]

Ian,

I would definitely consider upgrading to SQL server if you have that many invitees. I'm not 100% familiar with Access, but from what I do know that might be pushing the limits of its capabilities.