Accounting theory and practice, Volume 2 (of 3) : a textbook for colleges and…

2. _Supersession._ If no other causes than time lapse were operative,

the problem of depreciation would be a simple one, consisting of spreading the value of the patent over its life. In addition to lapse of time and operating simultaneously with it is the possibility of supersession. Supersession as an element of depreciation is the attempt to measure the probability of the patent’s being superseded before the expiration of its term by a better machine, device, or method. The measure of this element of depreciation is always speculative but should be attempted with the best judgment possible.