We also have unplanned experiments and or visitors. Hence, I've purchased a couple dozen sets of glasses for student use. Also, if I can confine hazardous activities away from the main benches, I'll put glasses at that station and tell people to wear them only when performing those activities. The biggest problem with safety glasses is to get the students to wear them. In our department, the Faculty are placed in the position of determining exceptions to the above posted rules.
Disposable aprons are available as well.
I also try to set them up at the stand up demo bench since they are less likely to spill stuff in their lap. I've seen a couple of emergencies were the TA lost their head and panicked. I'm trying to get away from glass pipettes in favor of pipettors with disposable plastic tips. Several labs have UTA's in them, they help provide eyes for spotting unsafe activities. Dispose of cracked and chipped glassware.