In California it depends somewhat on what county you are charged in as some are more lenient than others. But a 3rd DUI and leaving the scene of an accident: 6 months anyway. Plus the usual arrays of fines, alcohol treatment progarms, etc. You may be compelled to wear an anklet which signals if you have one drink and/or to install an ignition interlock device so you can't start your car if you have any alcohol on your breath.
Your question is way too complex to be answered in a short blurb. You need to candidly consult with a lawyer experienced in this matter. There are several on this site who will consult with you without a charge. I suggest you do so soon.
In Georgia in order to calculate the punishment for a DUI they measure from the period of the last DUI. Since you 2nd dui was 8 years ago, the pending charge would be a first DUI within a five year period. Here are the MINIMUM penalties for that:
First Offense Within a Five Year Period
$300.00 -$1000.00 plus any statutory surcharges.
10 days to 12 months, all except for 24 hours may be suspended, stayed or probated.
Theoretically, if your blood alcohol level is less than 0.08 grams %, you do not even have to do the 24 hours. Practically speaking, don't count on it. Moreover, on all DUI cases made on or after May 1, 1999, if you plead guilty or are convicted of DUI, you must be placed on twelve months probation less any jail time received.
The law requires a minimum of 40 hours of community service unless you are under 21 years of age in which case you must do at least 20 hours. The actual time is set by the Court.
If you are 21 or over, your license will be suspended for one year. You will be able to get your license back at the end of 120* days if you have completed an alcohol/drug risk reduction course (DUI school) and paid the appropriate reinstatement fee. During those 120 days, you will be able to get a limited driving permit.
If you are under 21, your license will be revoked for either 6 months (under 0.08 blood alcohol level) or 12 months (0.08 or higher) and no limited permit is allowed.
Now for the potential bad news. Since you have had actually a total of two previous DUI convictions, the Court does not have to sentence you to the minimums, as demonstrated by your second charge. I hope this helped.
First, it depends on the jurisidiction where the new charge is pending. Some jurisidictions in Ga. will try to put you into a DUI court program involving extensive treatment. In most places, you are looking at significant jail time if convicted. You need to speak with a lawyer who may be able to get rid of these charges, or at least mitigate them so that you don't lose your livelihood.
The answer depends on many factors. A big factor is the jurisdiction where your case is pending. In fact, you may not even be guilty so I would caution you not to put the cart before the horse and to consult an experienced DUI attorney. You owe it to yourself to do all that you can to defend this case since the stakes are so very high.