As I've mentioned elsewhere, I currently work in male mode. I began HRT a little over 4 months ago, and I have gotten to the point where a bra is necessary with some clothing to hide my development. I generally wear a bulky loose-fitting shirt with a spandex tee underneath, but as the weather here is starting to get downright hot, that's not really practical all the time. A bra at least keeps the nipples from being quite so obvious when wearing a lighter-weight top. I don't think the straps have been noticed yet; at least, no one has said anything.
I lost over 40 pounds at the beginning of last summer, and I simply could not bring myself to spend money on new mens' clothing. My compromise has been to purchase womens' jeans, slacks, tops and shoes that I feel I can get away with at work. With the exception of two shirts that are sufficiently bulky (see above!), I don't think I've worn anything made for men in six months.
I have to admit that it's not entirely due to not wanting to spend money on mens' things; it is a depressing thing to have to get into male drag every weekday morning, and the fact that everything I'm wearing was made for women (despite appearances) makes it a bit easier to deal with. I wrote about this a little in my blog 2 weeks ago; pushing the limits with long nails, pierced ears, long hair and so on helps me to feel that I'm making progress. I don't know, maybe part of me wants to be 'caught' so that I will be forced to come out.
I've even joked with some friends that if I transition at work slowly enough, maybe no one will notice!
Annie