On the issue of exchange (trade-in) of old asset for a new one, pre-FASB153's rule was based on exchange of similar and dissimilar assets, where gains on similar trade-ins are deferred (if cash was paid), much like how they are treated for taxes. FASB153 (implemented as a part of the harmonization effort with international standards) changed that. What is the key criteria used to evaluate these transactions in order to determine whether a gain (losses are always recognized in these transactions) should be recorded?