Are CSOs in T&T required to have an annual external audit?

We’re trying to figure out whether we legally need to get an external audit every year. We’re fairly small — our annual income is around $300,000. Our previous auditor retired and finding a new one has been expensive and difficult. A colleague told me that small NPOs below a certain income threshold don’t actually have to do a full external audit by law. Is that true? And if we don’t do a formal audit, what should we be doing to keep our finances in order and maintain credibility with donors?