How can we avoid needing a leap year/second? Given the Earth's current speed around the sun and current rate &amp; axis of rotation, what is the best way to keep time to avoid a leap year? How many hours should we have in the day and days in a year would keep things balanced to not need to add or remove days from the year? Further, how many minutes per hour and seconds per minute should we have to avoid a leap second?
Leap years exist for two reasons:


There are not an integer number of days in a year.
People perceive a need to keep the seasons where they are on the calendar.


Given the above, there is no way to avoid leap years, or something similar. Defining the calendar year as being a fixed number of days (e.g., 365 days) would result in the seasons shifting by one day per four years.



Leap seconds exist for two reasons:


The length of a day as measured by an atomic clock is not constant.
People perceive a need to keep midnight at midnight, noon at noon.


Given the above, there is no way to avoid leap seconds, or something similar. Defining the day as being a fixed number of atomic clock seconds (e.g., 86400) would result in your clock and the Sun disagreeing on mean local noon, but by a very small amount.

That said, there are serious proposals to eliminate leap seconds. Some people such as those who use UTC to timestamp financial transactions do not like them. So far, those proposals have been rejected. The standard response is that it's not UTC that's broken; it's using of UTC in a context where it shouldn't be used that is broken. If you need a monotonically increasing time scale, use TAI or GPS time instead.