How much should i be lifting?

[Soapyxii]

I start off with some big lifts each split as i want to increase them quickly for example,

Weighted dips 3 x F
Bench 3 x 5
Squat 3 x 5

Then hit a couple of tricep machines,

Seated tricep press 3 x 8
Seated dips (focusing on triceps) 3 x 8

Then either some chest isolation machines or free weights,

Seated chest press 3 x 8
Incline chest press 3 x 8
Pec dec 3 x 8

My question is how do i know when to stop, when ive lifted enough, when im past the point of gaining? I can keep lifting, obviously my lifts lower as i tire but as my routine is usually the same (im increasing weight) but i never really feel i cant continue or 'im done'.

I was in a rush today so my routine for chest/triceps was:

Weighted dips
Bench
Squat
Seated tricep press
Tricep cable pull-downs (rope)

I felt a major burn from just these lifts, but am almost certain you guys will say that's not enough for good gains.

Any in-depth help would be appreciated, remember, im still learning, dont troll so hard.

[VAnick]

Past the point of gaining?
What?

Lift 2 - 5 Work sets, of between 3 and 12 reps. Attempt more weight each time.

Stop when you begin to fail, or approach it. If you don't approach it by the 4th set, its too light.

[Farley1324]

Where are the pulling movements?