Q: Is it ok to wear ESD shoes or heel, toe, or sole grounders outside?
A: No. MIL-HDBK-263B Appendix 1 page 101 40.1.2 states, “Conductive shoes, shoe covers, or heel grounders should be used to discharge personnel on conductive floors. These items should only be worn in the ESD protected areas and should be kept clean so that contaminants do not inhibit their conductive interface with the floor.”
So, to protect your investment, for good house keeping and maintenance, longevity of the ESD personal equipment, just don them before going into the EPA and take them off when you leave.
Do this and keep them clean (vacuum inside of shoes weekly and maybe clean outsoles and grounders with soapy water once a week) and you’ll get more wear out of them and they’ll be more effective.