I would certainly go do it all over again. I was not able to do much before DBS. In 6 months I had gone from running a 5k to not having the strength to fix dinner. Today I cut the grass, cleaned the car, did two loads of laundry and cut down an over grown bush. Next I will fix dinner.
They will ask you a lot of questions and put you through tests to see if you are a good candidate. Primarily DBS helps with tremors and dyskinesia, so if your problems are more mental, then it won't help. So I would ask about what issues you have that might be affected.
I would ask about what exactly is involved in the surgery, how long it takes to heal, how long it takes to get the sensors adjusted so they do the most good. What are the risks? How do they address those risks? How many surgeries have they done and what percentage were successful? How long will the benefits last?