I am writing my PhD thesis in mathematics and there are several graphs to be included (on knots, braids, and other related objects). I know that there are several software available for drawing graphs like this, but I am not experienced with any one of those. Also I do not have much time to learn a new software to draw graphs. I have asked a related question before but am frustrated by the time that is needed in learning the drawing software. Am also considering using hand-drawn graphs.
My question: It is generally a requirement for the graphs to be drawn very nicely in a mathematical PhD thesis? (I know that different universities have different rules and here I am asking about the general principle.) Is it generally considered acceptable if I draw some graphs by hand, scan them and include them in the thesis?