Is it better to record Unrealized Gain/Loss in Value in addition to Depreciation Expense yearly for all fixed assets or only for buildings?

 

The dilemma I have is that MACRS depreciation schedule for buildings, for example, is applied no matter whether the building appreciates in value with time or not. 

For example, if in previous year, the building's market value was 300K, and this year, it's 330K, we need to record the unrealized gain in value for 30K.

So, recording the unrealized gain/loss in value shows the appreciation in market value, which is probably a good idea for buildings.

 

When it comes to cars market value though, I'm not sure if the unrealized gain/loss needs to be recorded in addition to accumulated depreciation. Since most of the time cars will have loss in value over time, recording the unrealized loss will be like recording depreciation twice.

 

I'm inclined to record the unrealized gain/loss in value only for buildings but would like to know if I'm on the right track or not.