Water pressure regulator

Well I would say yes! We had a non gauge fix one that I quit using as it seemed to restrict flow too much in low pressure parks. Then got to a now park, hooked up without it and toilet would not flush!! Needed to turn on faucet in bathroom to flush. Put the old regulator on and toilet worked fine. Seems this parks pressure was near 100 psi.
Now have an adjustable unit with gauge.