What is the state's obligation to ensure that a defendant is financially able to retain an attorney of his own choosing?

In view of the importance of these rights and the severe consequences which flow from their violation, the trial courts are required to "make all reasonable efforts to ensure that a defendant financially able to retain an attorney of his own choosing can be represented by that attorney." (People v. Crovedi, supra, 65 Cal.2d at p. 207, 53 Cal.Rptr. 284, 417 P.2d 868.) To this end, "the state should keep to a necessary minimum its interference with the individual's desire to defend himself in whatever manner he deems best, using any legitimate means within his resources...." (Id., at p. 208, 53 Cal.Rptr. 284, 417 P.2d 868.)