...but the odds are good that money spent on a new roof can increase basis & reduce your cap gains tax, even if commingled rather than collected separately.

Whether or not an item is assessed does not factor into the definition of "capital improvement."

While it's better if assessments are kept discrete, what you actually spend funds on is more important than how things are labeled on your budget. It's customary to take stock at year-end of what capital improvements--even small ones--were made using funds on hand. [Condo owners should get a yearly report on same to update their own books.]

Focus on keeping good & complete records of the actual improvements made.