I have a few questions about time dilation and how it accumulates. 1a. Say you have a situation where you have two clocks that move away from each other with symmetrical acceleration and relative motion. From what I understand, each clock would appear to have slowed down relative to the other, and this is not a paradox because each is in their own reference frame. Then the two clocks move back towards each other with symmetrical acceleration and relative motion. How would they compare to each other once they were back in the same reference frame? 1b. Same question as above, but assume there is instant acceleration. 1c. What if instead of moving back towards each other, they were teleported back together? 2. Though time dilation at earthly speeds is negligible in our every day lives, it still occurs. How is it that it does not accumulate over time and lead to small differences in our watches and such? Or, does it, but it is so small as to be unnoticeable? This applies to both gravitational and velocity-based time dilation, but I'm mostly interested in velocity for the sake of this question. Thanks!