What is the terminal date of eligibility for retroactive relief in a personal injury action?

Appellant further contends that, if retroactive relief is to be granted, the terminal date of eligibility therefor should be January 4, 1974 (the date the trial court entered its initial judgment upon remand), rather than May 15, 1972 (the date the action was commenced). According to the 'debt' theory which the trial court correctly applied in principle, any individual claimant's eligibility for retroactive relief could be held to have commenced on the actual date when he was 'first entitled to receive the aid.' (Bd. of Soc. Welfare v. County of L.A., supra, 27 Cal.2d 81 at p. 86, 162 P.2d 630 at p. 633.) On the other hand, a practical application of the theory to a class of claimants requires that retroactive relief be granted back to a single date which has some relevance and which is feasible, in practical fact, when applied to the class under the realities of the situation.