So I take my drumming pretty seriously, i would like to think i am pretty decent. I practice quite a bit, but i have one buddy that practices like a freak!!! What would you recommend is a good amount of time to practice per day without go insane. I love playing drums, but i can't practice for 4 hours straight. I enjoy long warmups though. Also, what to you recommend to help on inverted rudiments?

a good amount can be as short as 30 mins or as long as 3 hours.It all depends on you.
if you chose 30 mins,you can warm up for 5 mins.,do all your exercises,show music,rudiments,etc. for 20 and a 5 min. cool down.

now if you can dedicate more time it's better,I practice two hours daily and in only 1 month my left hand got significantly better.Just make sure if you do practice for extended periods of time, take at least a 10 minute break every hour to relax your muscles and brain.
I cant help you on inverted rudiments because i don't practice those,but also remember a drummer can practice for lets say 15 hrs and he/she wont go insane.

It varies from person to person. The last time I played competitively (DCA), I was probably practicing on 3 or 4 weekdays per week for up to 2 hours a day. (I was obviously drumming all day on the weekends during the season.)

My brother's one of those people who practices like it's an addiction. When he played competitively, he'd drum at least 2 hours every day, and often for 4 or more. Even after aging out, he'd play for hours multiple times per week "just to keep the chops up".

But even if your schedule prohibits you from drumming multiple hours at a time, you can still get in plenty of quality reps in blocks of just a few minutes. Practice often -- as often as you can -- and you'll improve.

As for inverts (and most anything else), I tackle 'em two ways:

(1) Play slow/moderate and with lots of reps. Get the feel and commit it to muscle memory so you don't have to think about what you're playing. Gradually speed up. Push your limits little by little, but stay in control.

(2) Isolate each hand. For example, with inverted flam taps, each hand plays tap-tap-ACCENT repetitively. Rep each hand alone to get the stroke down and work on heights. When you can comfortably play each hand's part, put them together.

30 minutes a day is never bad. But to be eficent, try going an hour or more. You don't have to do it straight... Just sit dowon, start warming up, then practice whatever you aren wanting to work on. Stretch frequently. Practice for half to an hour or so. Put the sticks down and come back later.

As far as your inverts go, one thing I'd like to add to Skydog's already well-put advice:

A valuable lesson that I learned from a number of my instructors is that you can only play fast if you practice fast. I don't mean that you need to start at a fast tempo. Practice at a slow tempo with the same exact technique you'd use with the fast ones. For instance, when you start with regular old flam taps, you're not going to be able to push out the triple strokes needed with just wrist after a certain point. You need to practice harnessing the triple stroke bounce at low speed and eventually work it up to fast speeds.

With the inverted rudiments, there's going to be a lot of need for a fast upstroke in order to pull the accents out. When you isolate each hand, make sure you're playing with the rebound necessary to create such an upstroke, and practice it slow and rep it up.

I say there is no sane limit to how long a drummer practices, its about how long other people can stand it before they tell you to stop beatin on that damn drum! :-p

AMEN^^^^^^^^^(My teachers hate me when I have my drum pad)

Some people can practice for hours and not get the quality of practice as an intelligent warm up would give you for thirty minutes.

Practicing should be focused on mental chops rather than physical chops. Good chops come with time, how fast and strong they appear, depends on your mind.

Not having any distractions at all is a good step. Always using a met is great. There are so many things you can do to improve your practice, without thinking of time.

The time you practice is directly relative to how hard you work. Like I said before, a 3 hour practice won't be worth anything if you don't actively participate upstairs.

Research has shown that you retain about 90% of what you learn during the first and last 20 minutes of practice, and only about 10% of everything inbetween. I practice in 40 minute blocks, with 20 minute breaks between them. I usually do two or three blocks of time a day, depending on how much time I have.