What is the difference between laches and prescription?

In the case of Sps. Aboitiz v. Sps. Po (G.R. No. 208450 and 208497, June 5, 2017), the Supreme Court held that:

"There is laches when a party was negligent or has failed "to assert a right within a reasonable time," thus giving rise to the presumption that he or she has abandoned it. Laches has set in when it is already inequitable or unfair to allow the party to assert the right. The elements of laches were enumerated in Ignacio v. Basilio:

 

There is laches when: (1) the conduct of the defendant or one under whom he claims, gave rise to the situation complained of; (2) there was delay in asserting a right after knowledge of the defendant's conduct and after an opportunity to sue; (3) defendant had no knowledge or notice that the complainant would assert his right; (4) there is injury or prejudice to the defendant in the event relief is accorded to the complainant.

 

"Laches is different from prescription." Prescription deals with delay itself and thus is an issue of how much time has passed. The time period when prescription is deemed to have set in is fixed by law. Laches, on the other hand, concerns itself with the effect of delay and not the period of time that has lapsed. It asks the question whether the delay has changed "the condition of the property or the relation of the parties" such that it is no longer equitable to insist on the original right.  In Nielson & Co., Inc. v. Lepanto Consolidated Mining Co. (125 Phil. 204 (1966) [Per J. Zaldivar, En Banc]):

 

Appellee is correct in its contention that the defense of laches applies independently of prescription. Laches is different from the statute of limitations. Prescription is concerned with the fact of delay. Whereas laches is concerned with the effect of delay. Prescription is a matter of time; laches is principally a question of inequity of permitting a claim to be enforced, this inequity being founded on some change in the condition of the property or the relation of the parties. Prescription is statutory; laches is not. Laches applies in equity, whereas prescription applies at law. Prescription is based on fixed time, Laches is not.

 

The defense of laches is based on equity. It is not based on the title of the party invoking it, but on the right holder's "long inaction or inexcusable neglect" to assert his claim. (Citations omitted)