My rule for cycling in the Alps was 'a pass a day keeps the doctor away!" My favorite stretch over four days was the Col de L'Iseran; the petit St. Bernard; the Grand St. Bernard and then of the many named 'col de la Forclaz' back to the area by Mt. Blanc.
I agree with other panelists that it comes down to fitness, gearing, and overall grade.
My best suggestion is to let your KNEES and legs tell you how they like the climb. You will have some ebb and flow with your overall power and strength, though if you keep yourself well fed, well watered and make sure ya have alot of carbohydrates, you should be able to climb day after day.
My biggest climb was in the Andes, starting at sea level and then up to 15,000 feet or so at Agua Negra between Chile and Argentina. Was climbing for 2 1/2 days. The air was thin and I felt woozy, even after a few cups of coca mate.
roughstuff