Can anyone offer advice on the best approach to managing address changes? Ie: should we simply write over old addresses or use a previous/alternate indicator? 

 We've got a small-size db (12,000 total with 1,500 annual donors) and have not been consistant in managing old address information thus far.

We personally write over the old address and update the "date from" tab.  It looks cleaner (less clutter) and we don't have any reason (to my knowledge) to keep old addresses.

We mark the old address type as Former - we put an ending date in the address. We create a new address if there is a change. We keep old addresses in case the post office or NCOA makes a mistake (which happens). We also may have a lot of folks that have seasonal addresses but we're not close enough to them to know it is a seasonal address, so having the address in our system already saves steps if they switch back and forth.

We save all old addresses as previous.   Even old business addresses.  The only old one we name otherwise is Parents address for our students/alumni.  It gives us a starting point to try and track down the alum.  We recently had an alumni directory issued and the company working with us tracked down quite a few new addresses by having an old address on the record. As mentioned, sending old addresses through NCOA (National Change of Address) can find a few people too.

We change address to 'previous address', add date to, and if possible document how/why it's not valid.  There have been numerous times with the address record has answered questions right away - many already mentioned in responses.  We find people are much more mobile than one might think at first.  Abiltity to track/keep on record several addresses was one of the many features we looked for when considering software. 

(Easiest way seems to be to use the 'constituent' drop down menu >>Copy preferred address to alternate or access it in 'address' drop down if you've opened address record. It will automatically change address type to 'previous address' and uncheck the preferred and send mail boxes.)

Lola, Looks like you have received several responses similar to mine - we track all old addresses using former address and an end date. This allows history continuity and reduces errors.

My 2 cents...

Karen