Just like the odds, there's no exact answer to this question because it varies from tipster to tipster. Each tipster has his own strategy on picking tips. Some tipsters like to risk more by givings big odds to increase the earnings, but will have a lower win rate and others will prefer ta less risking approach by giving small odds, but keep the winning rate as high as possible.
Each tipster average win rate, can be seen on his profile. You can see his all time performance or you can filter it by month.