I have ddog who is 1.5 years old (a cross breed). Tuesday to Thursday he is walked every morning for 40 minutes, lunch time 45 minutes to an hour and then 45 minutes to an hour again the the evening.
Friday to Monday he goes less walks, but much, much longer. 2-3 hours long for one walk, and also a short 20-30 minute walk.
Overall, do you think that's enough?