Time should not matter , cant remember last time disconnected battery for steering wheel removal just dont turn on key. Reason they used to want you to disconnect battery is cause they thought static electricity would detonate airbag. Now whenever you disconnect airbag on most it is automatically shorted via connector on airbag or any other part of SRS system that can detonate. If it makes you feel better disconnect it ,but it doesnt have to be just dont turn the key on.

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euro 287
Mercedes Technician 7 Years (retired to Hyundai)
2000 Dodge Durango
98 Mazda truck