How long after my wrist and thumb surgery should I wear my sling?

Ask your surgeon. Sorry, but the only person who's allowed to decide your guidelines for post-operative care is the doctor who is operating on you. That said, I'm guessing that you shouldn't need a sling very long, because the sling immobilizes your shoulder, not your elbow or wrist. Good luck.
As little as possibl. Slings do not allow much elevation of the wrist or hand, and prolonged use can lead to shoulder and elbow stiffness. Since the surgery was on the hand, I would recommend not using the sling at all. Keep your hand elevated above heart level as much as possible for the first few days, then as needed based on the swelling you have.
Depends on your doc. I tend not to use slings for hand surgery because it does not elevate the hand as much as I would like. I usually tell my patients to carry the operated hand over to the opposite shoulder (kind of an exaggerated pledge of allegiance) in order to keep it above the heart and help reduce any post-op swelling. So check with your doc since we all treat differently.

Related Questions

Having's trigger thumb surgery left hand w carpal tunnel already had carpel tunnel on my right is the trigger thumb surgery the same, please expln?

Probably. Carpal tunnel and trigger fingers can coexist and may be related to conditions such as repetitive trauma or diabetes.
They are similar. Carpal tunnel release is incising through a ligament to decompress a pinched nerve. Trigger finger or trigger thumb release is incising through a tendon sheath to allow more room for the tendon to glide smoothly. As far as recovery they are similar. Both feel like a bad cut for a few days then the pain resolves. Sometimes therapy is needed. Adhere to your surgeons post op instructions.
Trigger finger. Limited mobility in the finger, pain where the finger meets the palm, often called the finger palm crease, pressure causing pain can be a sign of stenosing tenosynovitis or trigger finger it is treated by antiinflammatories, corticosteriod injection and perhaps surgery if symptoms do not go away.

I am 4 was post op from cmc thumb surgery. Just got my cast off now in a spica splint. What are safe hand exercises I can do? I have very little rom

Post-op thumb care. If you are still in a splint, then your surgeon only wants you to move joints that are not splinted. Generally, at this stage gentle rom is allowed if you have had a trapeziectomy, suspension arthroplasty and ligament reconstruction with a split tendon.
Cmc arthroplasty. Typically needs to have hand therapy by a specialized therapist. Talk to your surgeon about what the next step is.