Most agree that, as was originally intended, the parole system puts a necessary focus on rehabilitation, despite its current problems which are widely debated. Critics note that it is becoming more and more expensive to the taxpayer, with little evidence of successful rehabilitation for prisoners. The conditions of parole themselves are often attacked as well, critiqued for being overwhelmingly criminogenic and perpetuating mass surveillance and a permanent state of imprisonment that does little to ensure a smooth reentry into society. Critics note that greater discretion is required to decide which parolees requite costly supervisory resources and which ones do not, rather than placing digital, physical, and structural restrictions on every parolee.