i would suggest if your spraying for livestock farms who are not RT for crops, 3 years is fine.For livestock assurance you dont need an annual test its every 3yrs. Could I contract spray for other livestock assured farms on a 3yr test? Been doing annual mot just to cover myself for the contract work. The sprayer has anything it needs as it needs it but would save the cost of test and the many phonecalls to remind them its running out/ run out
If your spraying for farms who are RT against spraying, you need it 12 monthly