Walking and sleeping

Hi All,
Long time stalker first time poster (also posted in the introduction thread).
My Hank is 15 weeks old and I am wondering how much and for how long he should get walked? The past two days i have taken him out in the morning for about 30mins and then we come home and play and then he gets tired and has a sleep.
He goes out for a toilet break mid morning but really doesn't want to walk, he likes to do his business and then jump around on me.
I take him out again for a walk in the afternoon and one before bedtime.
Is this too much as he seems to be sleeping a lot of the time (this may be normal...first staff pup i have had).

Also, when i return to work, i will walk him in the morning and he will have access to toilet outside and someone will come and walk him round lunchtime, wonder how long that walk should be? He will also be taken out when i come home from work and again before bed.

Would be interested in your thoughts!

Thanks

My staffy is almost 5 months old and she still sleeps for most of her time - this is normal.

In terms of exercise, I've heard of the 5 minute rule for each month of age so you'd be at about 20 minutes 2-3 times a day.
Are your walks also his toilet breaks or does he have access to a garden or similar ?

Thanks Nifty Staffy.

Ok that makes sense. No he has access to toilet outside if he is at home. I have been taking him out mid-morning and he goes to toilet then but i am only doing this because i am at home with him for the next few days. When i go back to work he will just go outside when he needs to go in-between his morning and when he is walked at lunchtime-ish.