A friend of mine, who had a 4th gen maxima before told me that if I considering lowering the car in any way, I have to get camber kits, otherwise the tires will wear out very fast. Is it true and why? I want good quality springs, but with low drop; just enough to improve performace/handling; so I guess I'm getting Tokico kit.

Also, if I lower the car, say by initial 1.5" front, 1.3" rear; will it increase over time, say in 5 months?

thanks.

Yes the springs will settle marginally over a few months. No you wont need camber kit with the tokico package. Anything lower than 2", camber kit is a must cause your toe out will be increased, causing the insides of your tires to go bald in no time, while the outer edge remains in good shape.

I've had my Progress springs on the car without a camber kit for about 6 months. I do about 110km every weekday and my tire wear is normal. The tires on the car are pretty big(225/60/15) so I'm not sure if the flexibility of the sidewall has anything to do with the wear.

You might wanna consider the camber kit. I have a very minimal drop (H&R 1.4" front, 1.3" rear) and my front tires get some more wear on the inside edge than the rest of the tire. My last set of tires had about 2mm left on the outside, whereas the inside was smoothed out. The camber kit will correct this.

the lowered suspension will settle over time, but it won't change too drastically from the initial install

Also make sure to get an alignment after the install.

I got the Tokico kit, and I did not need a camber kit to get the alignment within specs. Dropping the car doesn't cause tire wear, unless there is still negative camber after your alignment. As long as your car can be, and IS, aligned back to within specs following the intstall, you should not have premature/uneven tire wear.
Unless, of course, your new suspension encourages you to double the posted speed in every single corner. That may be a little wearing on your tires.

when i lowered my previous car, mitsu eclipse, i had tokico with eibachs. It lowered the car about 1.7". I bought a set of INGALLS camber kits. Don't get it at first.. If you notice the uneven tire wear, then get it.

Ya jeeeszus just look at your sig oyur car is definitely not within alignment specs. The outside edge is way to out placing too much wieght inside, nice for the curves but bad for the rubber.