Lessons I wish I'd had more often

There are many lessons I wish I'd learned or learned better while I was in school, but there are also lessons I did get that, as far as I can tell, most students of art either do not get or do not heed.

A while back I was fortunate enough to win a set of 45 soft pastels, I haven't done much with them yet because I haven't had much experience with pastel. Today in getting ready to use the pastels I went through with the research I'd done on the pigments in the pastels; of 45 pastels, there were 14 to 21 pastels that I feel good about using. There are 14 pastels in the set that were both single pigment colors and non toxic, the other 7 are non toxic but with two pigments per color. That's not quite half the set that I feel alright about using.
In all of my art classes I recall one painting or drawing teacher (excluding print making classes) who taught us to be careful about the materials and pigments that we used. This teacher taught us that we needed to be aware of the materials we used for two reasons: the first reason was for our own personal safety (and that of those around us), and the second reason was to make our work of an archival nature, such that it would be able to last for ages.
Artists through history have a reputation of being weird and crazy, some probably came by that naturally but for many it was the result of the media they worked with: lead poisoning from their paint, etc. There are so many toxic or potentially toxic art materials out there, from the pigments themselves, to paint thinner, etc. An example in my personal experience was when I was able to use a shared studio space I happily worked there, but if one or more other person was working in the studio, the fumes from their paint or paint mediums started giving me a headache and I had to leave. There are a lot of potentially dangerous things used to make art, it's important to be informed so that you can use something safely (something may be dangerous in one form but not in another, or may be safe with the use of an air filter etc.).
The consideration of the archival nature (or lack there of) is a very important one. Paintings (other media as well but painting is what I know best) have the ability to last for hundreds of years if the right materials and techniques are used and they do not suffer any undue misfortunes. On the other hand, some of the most beautiful paintings can be lost or greatly altered before their time if not done archivally. As much as I love Leonard daVinci, The Last Supper is a perfect example of this; daVinci used an experimental technique which unfortunately was not a winner and as a result there has been a very real struggle over the years to preserve this masterpiece from itself. Making something archival comes down to the materials you use and one consideration is pigments, and the possible chemical reactions between them. If you happen to unknowingly combine two pigments that have a reaction, it could change the coloring or look of your finial product.
Check labels, do your research, be safe!