Sample size play a very important role in every research you undertake. That is why it is very essential you gather enough information about your subject. In statistics, a sample size of at least 30 is considered large enough, however, the larger the sample size, the more accurate information you can obtain and generalize your result to the entire population.
In other words, the larger the sample size, the closer your sample statistic will be to the actual population parameter and the least error you can recall in the study. Also, remember that the sample size obeys the law of diminishing returns. i.e. as you increase the sample size, it gets to a point where successive increase doesn’t really add any effect but rather reduce the accuracy of your output. That is why you need to ensure that your sample mean approximate the population mean, hence exhibiting the properties of a normal distribution.