If you don't need a Class 1 there is absolutely no point in spending any money renewing it. Once you have held a Class 1 just go to a AME and renew it when you need it. The validity periods are clearly listed on the reverse of the Medical Certificate.
Class 2 -60 months under 40 but not beyond your 42nd birthday
Class 1 -12 months to age 60 6 months for CAT over 40.
A no brainer really!