For how long you can exercise, I say just feel your way through it. If you can last an hour at the gym then that sounds great. If you work out on consecutive days, remember to alternate your workouts (ie- if you run on day one, use the stationary bike on day two) as different exercises work different muscle groups that need time to repair themselves.
If your just starting out I say just go and do what gets your there... however after a while....
I actually find it better if I plan what days I will and will not go to the gym then I go without thinking about it instead of saying oh I can go Saturday to make up for Tues or something... Its easy to do and then Saturday comes you dont go you get teh idea.
As for skin, no way to tell! You will have to loose to the weight and wait and see
Having a set routine might help you be more consistant with your workouts, instead of doing what you feel like or playing it by ear. Left to my own devices I tend to do mostly cardio, so I schedule certain days to do weights, pilates etc. For example, if its Friday it must be weights day, or if its Sunday then I do cardio.
On the internet no one knows you are typing with your beak.
An exercise in futility still counts as exercise!!
"There's a pattern to the randomness!" ~ Artie ~ Warehouse 13
"That's the only break you get, so I hope you enjoyed it" ~~Cathe, STS, Meso 2
"Weakness is hard, but weakness doesn't have to mean defeat!" ~ Lysa TerKeurst
I think having a routine is good. I planned what i was going to do for two weeks at a time. I've been on this wagon for a while and never really did a routine just did what i felt and never seemed to stick to it. This time i do have a routine and seem to be sticking to it and feeling it a lot more. As for as the extra sink i don't know. I think about it too. I even told my husband that if i have extra skin i'm going to get a tummy tuck.But I do use firming lotion daily supposed to help put the elasticity back into the skin. Now if it really does or not i'm not sure but doesn't hurt.I really hope it works. Oh lets just pray that ther will be no extra skin!!
Like eating, I think you need some sort of structure working out. I wouldn't want you to go to the gym and not see results or see the results you want and get frustrated.
You can always go to whatever classes are offered and I know a lot of people enjoy gym classes. One thing I'd say is there is a lot of good routines out there though. Body For Life and The New Rules of Lifting for Women are 2 books I'd recommend. They include weight lifting and cardio routines.