If someone has basically no refractive error, what is the normal reading glass prescription as he ages? also do things like the dashboard get blurry?

Normal presbyopia: From around age 40 the lens cannot focus near objects as clearly. Use over the counter reading glasses to help.

+1.50: At age 42 you would likely need +1.50.

Presbyopia: Is the term for the loss in focusing power of the lens of the eye with aging. Yes, the dashboard may eventually get blurry. Smart phones cause more eye strain than we used to have.There can be small variations. Age 42-44: +1.25 45-48: +1.50 49-52: +1.75 53-56: +2.00 57-59: +2.25 60+: +2.50.