A few things will matter....
1- do expect to have sentinel node biopsy or many nodes taken?
2- are you doing immediate reconstruction?
3- are your range of motion and strength pretty good now?
On one - the more nodes taken, the more difficult is recovery. I had just one node taken via sentinel node biopsy. I had bilateral, and the right side (snb side) had less range of motion and quite a lot of numbness.... The left was easy breezy.
On two - if you have reconstruction, they place the tissue expanders under your muscles. That makes recovery a little more difficult.
On three - if you have good strength and range of motion before, then you will do better. So, it is worth it to stretch and exercise BEFORE the surgery....
My experience - I could reach up to eye level with little difficulty practically right away. Anything higher, and my better half came to the rescue and we stored key items at a lower level. At one week, I had no problem raising my arms above my head. I had bilateral, sentinel node biopsy on the right, and no reconstruction. I had very good range of motion and strength before surgery, and I am positive that this made a huge difference. I rode my bike on day six after surgery, and it felt totally fine.
The biggest annoying thing was the drains... They place drains so that you don't get a build up of fluid in there.... And the drains get in the way and are annoying. When you are allowed to shower (for me, I think it was 48 hours because I had glue rather than stitches), hang your drains on a lanyard.... And shower away. When you are out in the wild, wear clothes that allow you to stick them into pockets... Ad no one will be the wiser.
GOOD LUCK! When is your surgery?