I can do all the major and minor scales and practice them daily.
Should I start to try and do them hands together?

Why not? You'd be able to do them in the half the time!

Wow - really ALL of the Major and Minor scales? (or a defined set?) ..And you not doing hands-together?
Hands-together is a critical skill that you also need to develop. your hands need to learn to work together (and your mind needs to learn to control them.

Hands separate is good for figuring out or learning really tough stuff and getting hand independance, but you need to be able to do hands together too - especially important for sight reading and easier material.

(IMHO of course)

By all means start doing them hands together, but start with one octave white key scales. Go slowly at first being sure the fingers match up correctly. Then go through the flat and minor scales, also one octave. Then start adding octaves. With each new step, go slowly and be sure your fingering is correct.

Reason I emphasize going slowly in the beginning is playing hands together is another skill to develop. But scales are a great exercise and important for your music theory knowledge. We just had (have) a long thread on scales in the Teachers' Forum.

Joan

Hands together gives you a lot of options for scale practice: single or multiple octaves, unison or contrary motion, varied rhythms or dynamics. You can also play scales "at thirds" or "at sixths" which just means starting one hand on the root of the scale while the other plays the same scale starting on the third or sixth degree.

Alfred's "The Complete Book of Scales, Chords, Arpeggios, and Cadences" has a good appendix with scale practice suggestions.

Our own Kreisler has an online guide to scale practice you might find useful. Download it here.