As a former "client',I wanted to embrace the idea of recovery,and went into a tc. But,left after 90 days. Most addicts enter rehab for two reasons..to beat the legal system,or because they want sobriety. However,based on my own experience,it took YEARS of incarceration before I had that fundamental change in my thought process,which is needed if anyone is to stay clean.
To answer your question,a 30 day program is a very minor step in the right direction, one which I'm SURE will "take" in some, but not many...it takes much longer to begin that "change" that MUST take place if a person is to stay clean, no matter how much they may want to stay that way.
30 days may "dry" you out,and educate you to an extent,so,in that fashion its practical.But as I said,you must have a change in your core thought process for you to stay clean,no matter how much you may want it.
I,m proud to say that after 25 years of hardcore addiction,I'm now 5 years clean,and a college freshman ,studying social work and substance abuse.