I adjust the pressure in the spares on both vehicles every 4-6 months during a routine tire pressure, fluids, and lights check. The jack and tools for my truck required and owners manual consult to find and I'm glad it was in my driveway during a self education moment and not on the side of the highway.
On a related note, my brother called me at work one day asking what could cause his tpms light to remain on even after he checked and verified that the proper pressure was in his tires. I asked about the spare, of course he hadn't, nor had he even lowered the spare in the previous 5 years he owned the truck. Bring the pressure up to the sidewall max pressure (from 10 psi) he was good to go with no lights to bother his rythem while jamming Five Finger Death Punch at full volume.
On a related note, my brother called me at work one day asking what could cause his tpms light to remain on even after he checked and verified that the proper pressure was in his tires. I asked about the spare, of course he hadn't, nor had he even lowered the spare in the previous 5 years he owned the truck. Bring the pressure up to the sidewall max pressure (from 10 psi) he was good to go with no lights to bother his rythem while jamming Five Finger Death Punch at full volume.