Just to reinforce Breighlin's comments about it being different for everyone, here are my answers.
1) I feed on demand but, at 17 weeks, I'm starting to get more of a sense of when he wants food. The only feed that his set in stone is his pre-sleep bottle of EBM which he has at 7 every evening. Feeding on demand is the only way to start. Most babies will settle into a bit more of a schedule by 12 weeks.
2) I find it much easier and more convenient to feed from the breast (no faffing about with sterilising bottles). But we decided to make sure that he could take a bottle so introduced one a day from when he was six weeks. I have to express twice a day to get enough for him which is a bit of a pain, but it does give me some more flexibility.
I actually found it really hard to express to begin with. I had to switch pumps (from manual to electric) and even then it took me a while to build up a sufficient supply. But that is just my experience.
3) I store the milk in bottles overnight and any excess gets frozen in storage bags. I have been told that refrigerated milk can be stored for up to 5 days in the back of the fridge (not the door) but I don't leave it for longer than 48 hours if I can help it. Frozen milk can stay in the freezer for up to 6 months.
4) I am planning to breast feed until I wean him onto cow's milk at a year because I work from home. As I say, he takes a bottle anyway which means I can take the occasional evening off. However, one of the mums in my mum and baby group weaned her son successfully on to formula at 3 months and I know another woman who his planning to wean her son at 4 months. If they will take a bottle of EBM from a reasonably early age, I think it is fairly easy to make the switch to formula.
5) I have yet to have night out (my first was supposed to be this Friday but it was cancelled). I will be going out in a couple of weeks, leaving him with my mother. The plan is to leave 3 bottles of EBM, one for bedtime, one in case he wakes before I get back (he still doesn't sleep through) and one for emergencies. I am currently freezing as much as I can in preparation.
As I say, I express twice a day, once in the evenings when my husband is giving Peter his bottle and once during his morning nap. I get about 5 oz in the evening and 2-3 in the mornings because it is between full feeds (rather than replacing a feed as the evening one does if that makes sense). It seems to work fairly well, although there are days when I feel as if I am an industrial milk cow. Expressing is one thing I won't miss when Peter is weaned!
One thing I would say, I found getting breast feeding established much, much harder than I anticipated. This was due to a variety of things, including the shape of my breasts, my son's temperament and the quality of the midwives on the ward when he was born. So I would say be prepared for anything. It is worth persisting - I really enjoy feeding him now - but it can be incredibly tough so don't feel that you have failed if it doesn't live up to your expectations.
Best of luck. And I hope you have a happy, healthy rest of your pregnancy.