Turbo trainer , 30 mins intensive ?

[neil-935ql]

So , with winter loming just round the corner it's time for the turbo trainer , just wondering what I should be hitting on the turbo , yesterday I did 75 mins doing sprint bursts every 15 mins for about 2 mins each sprint , I have tried 30 min session and a 45 min session not to sure what's the best to hit really , seen online the 30 min intense session is popular , what are you up to on your turbo ? Any top tips ?