Hi @elle1948 - everyone's experience is very different. In my case: I had a left vertical skin sparing mastectomy in April last year and an Aeroform tissue expander inserted. I've had no trouble at all with the tissue expander (except for the initial pain, which comes both from the mastectomy operation and the nerve pain from inserting the expander under the pectoral muscle and then slowly expanding it, via a remote control, over time). The benefits of the Aeroform are that you can self-administer the C02 gas which expands the tissue and this can be done in small amounts, so that the pain that many experience from the saline injections one can be largely avoided. The drawback is that the expander, once full, feels a bit like you're wearing a handbag on your chest and there's a bit of swelling above the breast, just below the collarbone as the expander is circular and this is the top of it. It's not like the teardrop boob ideal - but it works for me! :p Also, it's not so easy if you're a tummy sleeper...but you can get around this by creating a comfy pyramid of pillows.
Then, once full or to the size you want, you go into what they call 'maintenance mode' and this means just adding gas one once or twice a week as it leaks 2-10% (depending on the version of the expander your PS uses).
I don't <3 my expander, but it hasn't been awful. I have given it the nickname 'Brenda' and have enjoyed the fact it has given me a cleavage where there wouldn't have been one. In a couple of days from now, my PS is taking out the expander and creating a new breast from my own tissue via a DIEP operation. I'll be happy to say goodbye to Brenda, but acknowledge she did her job for the 12 months we were together :). She also gave me time to get fitter, lose more weight and plan and prepare for the much bigger reconstruction operation (mentally, emotionally and logistically). It was 12 months I needed.
I am lucky in that (1) I don't bruise too badly, (2) I heal well and (3) I don't scar too badly either. Your Plastic Surgeon will be the best one to give you advice on this.
Good luck
Nikki x