If you have odor problems in the house, the risk is high that it originates from the crawl space. Because you get used to smells, it may be difficult to feel mould odor in your own house. Therefore, ask someone about a statement. Can he / she feel a bit of mould odor? It may be a little sensitive to tell someone that you smell mould at their house, so people might not say anything, even if it feels clear, so make sure you get an honest answer.
The house can, however, be attacked even if there is no mould. To be sure not to be surprised by problems or to be subject to damages for sale, it may be good to have a inspection of the crawl space.