A wearable device (400) comprises a first and second transmitting loops (103A, 103B) coupled with said wearable device, said first and second transmitting loops being coupled with a data processing unit (104). Additionally or alternative the second transmitting loop (103B) may be coupled with a sensor (101) outputting a measuring signal. Said first and second transmitting loops have a property with a readable value depending on aging of the object of a wearable device. In addition the data processing unit (104) is configured to measure the value of said property of the first and second transmitting loop and thereby determine effects or amount of aging.