By what time a person should make hte transition from pool to solo any idea or inputs??
To answer that question you need two other pieces of information besides your own hash rate. You need to know what the current total network hash rate is, and you need to know how long you are willing to wait to find a block.
Are you interested in solo mining if you are likely to find a block once every 1,000 years? How about once every 10 years? Once per year? Twice per year? Every month? Every week? Every day? Hour?