Most Arizona insurers raised marketplace rates by 25% to 30%, but some residents are seeing even steeper increases. Scottsdale retiree Darryl Komesu says the premium for his current plan would nearly triple. He plans to switch to a less expensive plan, but worries its reduced coverage could put his retirement savings at risk. Open enrollment runs through Jan. 15, with a Dec. 15 deadline to select coverage starting Jan. 1.