Simpler explanations are, other things being equal, generally better than more complex ones.

No more things should be presumed to exist than are absolutely necessary.

3 is a prime, 5 is a prime, and 7 is a prime. Why bother with non-prime numbers when the primes can do everything?

For nothing ought to be posited without a reason given, unless it is self-evident (literally, known through itself) or known by experience or proved by the authority of Sacred Scripture.

Intuitive cognition of a thing is cognition that enables us to know whether the thing exists or does not exist, in such a way that, if the thing exists, then the intellect immediately judges that it exists and evidently knows that it exists, unless the judgment happens to be impeded through the imperfection of this cognition.

Entities should not be posited unnecessarily.

Pluralitas non est ponenda sine necessitate. A plurality (of reasons) should not be posited without necessity.