Correct, the tire is under inflated hence it wears more on the edges. Normally tires can last at least 40-50k km if your pressure and alignment are proper and you drive normally, not whacking the corners all the time.

Going around turns at 60 is depending on the turns la. If sweepers, 60 is very slow. If U-turn then 60 will make your tire screeching already.
Age does not play a part in tire wear, more on the elasticity of the rubber.

If camber is too negative, then usually it will wear on the inner side of the tire. If too positive then will wear the outer side.
If too much toe out, also will wear inner side more. If too much toe in, then usually will wear more outer side of the tire.
If wear out both inner and outer side, usually tire under inflated.

Why rear still ok? Because front does a lot more work for FWD cars (putting the power down and steering the car at the same time). Weight distribution of FWD cars are also more at the front, hence more pressure put on the front tires. On top of that braking also is much harder task on the front tires.
So normally front tires for FWD cars would need a few more psi of air/tire pressure. If you put the same as the rear then the front will tend to wear out much faster. Even if you give more pressure to the front, it will still wear out faster, hence you still need to do tire rotation to even out the wear all around.

You're supposed to rotate every 10K. It's possible for the front to be worn out much faster if you under inflate and you don't rotate, then do a lot u-turn at 60kph.

You can just buy 2 tires and use them at the front since the rear are still good as you said. Different brand is still ok as long as the same for each axle. Might not be ideal but still very much acceptable.

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Added on November 20, 2012, 10:13 pmThe booklet or sticker is a good starting point. Heck it's already as per manufacturer suggestion since they are the ones who build your car so they should know better lah. I personally like to increase by about 3psi from the sticker suggestion. If I feel still a bit to soft and not as sharp response, then I increase further. If I feel it's already to harsh in therms of ride comfort, then I reduce a bit. I keep doing that until I find the pressure I like. Btw the car dictates more in terms of the ideal tire pressure, not so much the tires it self.

This post has been edited by 6UE5T: Nov 20 2012, 10:13 PM

Check tire pressure every month. I normally do this every 2-3 weeks during fill up at fuel stations.

Rotation does not necessarily need alignment if all your tires are more or less the same condition. That's just the workshops trying to make more money out of you! The rotation it self should be cheap la, only jack up the car and open bolts what? Heck I used to do it myself few years ago!

Some tires will screech more than others. But yeah, no screeching means in general not too bad. I often corner until my tires are screeching loud but yet they are still in good condition after 30K km!

Again as I said before, it's not true that tire rotation always have to be followed by alignment. Those who said that don't know anything, or they are workshop owners who want to make more money! Anyway it's up to you if you want to believe me or not, it's your money after all so do what ever you think is right for you.

In terms of tire pressure, well the look of it can give you some indication but not enough. Normally the tread pattern have to lie pretty flat on the road.
If you prefer less pressure then that explains why your front is worn out already on the sides.

Yes, surely no need balancing ever if just to rotate. Balancing is needed if you experience vibration in your steering when doing certain speeds. If you dismantle tire from the rim, then you will surely need to re-balance once you install the tire back.

Yes, as long as your steering is still straight then no need alignment even when you do rotation. Tire rotation depends on what tire you use.
If non-directional then you can go criss-cross or X pattern first (rear right-front left and rear left-front right), then the next rotation is just front-rear without changing left-right. Then next rotation follow X pattern again.
If your tires are directional, then you can only do front-rear and not left-right, unless you dismantle your tires and change the assignment to the rims from left to right and vice versa.

If you pump too much then grip will be compromised and the ride will be harsh. But under inflating also may loose you grip even though seems more comfortable.

Yes I would if I'm still using the std rims though.

Not really significant difference if rotation every 10K km. If you rotate when tires already quite used up like you now, then it will give some impact. The reason I include the spare is so that the spare rubber will not get brittled and this prolongs life of all 5 and wear more evenly for all 5. Of course when all 5 worn out then have to change all at once. But that's just my personal preference since I prefer all my tires are the same. But if I'm using after market rims like my daily car now, then of course I leave the spare in the trunk forever.

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Added on November 21, 2012, 3:01 pmMe personally I don't do wheel alignment based on mileage used. I only do when I feel it doesn't feel right anymore, and it can be even up to few years or 20-30k km before I send for alignment. Because often the workshops actually misalign/don't do properly which causes the steering to be worse/not straight anymore! I'm also a bit picky on this so once I got the right feel, I'm reluctant to have it change unless it already feels not right anymore.
Same also with balancing, if it's not vibrating up to 180-200kph, then I never send for balancing. But for me normally balancing will be a bit more often than alignment cuz the balance can change sooner when you lock during braking or often whack corners hard which causes the tires to get worn out faster. Also often the balancing weights come off.

This post has been edited by 6UE5T: Nov 21 2012, 03:01 PM