All condo/townhouse/planned unit developments basically handle HOA maintenance the same way. As defects are discovered by owners, those defects are presented in writing, (typically via contractor bids or inspection reports), and then the HOA board decides if and when to have those items corrected. Part of the HOA payment goes towards a Reserve account. This account is used for paying commons-area maintenance and repairs. If the Reserve account does not have enough money to cover a needed repair, then either a Special Assessment is charged to the owners or the HOA dues are raised to pad the Reserve account to pay for the repair in the future.