You know my stance. If you are buying because you feel it is best for your family then that is fine. If you are buying because you think that San Marcos is at or near a bottom, then I absolutely disagree. I feel that over the next 2 years San Marcos and heavily built out areas in NC may indeed follow and Eastlake path, (if you are familiar with Eastlake down in Chula Vista) then you know what I mean.
As for trying to measure the bottom, yes you may want to do a price calculation and when you find it is much cheaper to own then to rent, indeed you will see investors jump in. Also the process for rental property purchases has feedback. If lots of investors buy rentals then the inventory of rental property grows, and rents go down due to competition… Thus the purchase prices get pushed down even more.
I do not agree that 10% is the maximum downside risk to San Marcos.
Again though, some people buy because of other reasons then timing the market. Just make sure that if you buy now, you are okay with further depreciation that may well (better then 50/50 chance) exceed 10% in San Marcos.