Here are a number of factors that can sway the value of your condominium in any given month:

1) Time of year

The Center City condo market is HEAVILY weighted towards the spring. Selling a condo- especially a one bedroom condo may not pull nearly as much in any other time of year.

2) A spate of foreclosures or short sales in your building

Yeah, that always sucks- but a number of short sales or foreclosures can drop values fairly quickly within any given building. So can an auction.

3) A huge special assessment

Though an assessment does (in time) help improve values, the onset of one might temporarily reduce demand for a particular building. ALL buildings have assessments from time to time and it's unavoidable.

4) A large number of similar properties for sale in a building

Uncommon, but if several condos within any building hit the market, the value of your unit may be affected.

5) The state of the economy

If the market overall is depressed then the value of your condo will decrease.

6) Showing ability

Perhaps your condo used to "SHOW LIKE A GEM" but now has three frat boys and a dog renting the place. Think that's not going to affect value?!

You'd pretty much have to be from another planet to think that arrangement won't affect a condo's value :-)