How long can one be on benzodiazepines hypothetically when starting on a low dose (e.G Xanax (alprazolam) 0.25 mg) until tolerance induction?

No time limit. Tolerance can develop quickly with medications like xanax (alprazolam) and is the main reason fot them to get abused. It is advisable to be under a physician's care to ensure the medication is treating the symptoms for which it is prescribed.