Unfortunately, there is no "per unit" or "safe" amount that you would look for in the Association’s financials, nor is there any particular formula to use. The amount which should be set aside for long-term maintenance may be drastically different for each different Association, because all Associations have very different maintenance needs. For example, a homeowner association with a community clubhouse and pool will have much higher common area maintenance needs than a homeowner association with no common areas other than a sign at the front of the neighborhood. In the world of condos, there are generally more "common" items that are paid for by the Association than would be found in an HOA, but every condominium regime is structured differently with regard to which portions the owners pay for and which portions the Association pays for.
Notwithstanding the foregoing, you should obtain and carefully inspect the most recent reserve study for any Association you’re interested in buying into. Both the Condo and POA Acts require that all Associations perform a reserve study at least once every 5 years, and that they re-visit the results of that study at least once every year. The reserve study is supposed to show a breakdown of all of the long-term common area maintenance needs of the Association, and then give a suggested amount which should be collected from the owners each month so that there will be no large or unexpected special assessments for maintenance in the future. If you find that the Association has no reserve study, that’s a warning sign that the Board is not keeping track of reserves and maintenance responsibilities like they should be. If you do obtain a reserve study, then you can compare the findings in that reserve study with the financial records of the Association to see if they’re staying "on track" with how much they’re supposed to be collecting and saving each year.
Generally, you are not able to get access to financial records or reserve studies for a condo association until you receive what’s known as a "resale package." And you generally do not obtain a resale package until after you’ve signed a contract to purchase a condo unit in that association. From the date you receive the resale package, you only have 3 days in which to review the package and cancel the contract if you see something you don’t like. Thus, there is a very narrow and specific window of time during which you can obtain and review the information needed, and to make a decision on what to do. The details of resale packages for condos is described in Virginia Code Section 55-79.97.