Not only are there plenty of old* Sonics running tunes with no ill effects, there are plenty of folks who decline to tune or do anything else until their warranties run out. Silly, IMO, but it is the opposite of "don't tune it unless it's new," an idea I haven't seen anyone but you express.
*the Sonic first came out in 2011, which means there are no "old" Sonics, only some that are a little older or have a few more miles than others.