The minimum recommended verification frequency by obligation type is: Monthly — EPF ECR and ESIC challans (both due by the 15th of each month — verify payment by the 20th); wage registers and muster rolls (verify alongside challans each month). Annually — CLRA licence renewal (verify the renewed Form V before expiry); annual return filings (contractor Form VI-B half-yearly returns due 30 September and 31 March; principal employer Form XXIV due 15 February). At engagement — onboarding checklist covering all statutory registrations before work commences. Quarterly or biannually — formal vendor compliance audit covering all obligations simultaneously, producing a scored compliance report. Monthly verification of EPF and ESIC challans is non-negotiable because these are the two most expensive liability exposures for principal employers — and both can be resolved quickly if caught early.