Q.Tiny red spiders
Sometimes I come upon a batch of tiny red or yellow spiders all concentrated on a web. I used to just spray them with bug killer, but now I’m thinking they might be beneficial. What species of spider are they?

Certified GKH Gardening Expert
It would be impossible to give you an answer without photos, a description of what you found them on, and if these were on your plants.
If these are very hard to see, and this webbing is occurring on your plants, then you may have a HUGE problem. Spider mites will make short work of any plant.
Please include photos, and as much detail as you can, and I will be more than glad to help.
Unfortunately, without knowing whether this is a plant eating mite or an insect eating spider, it would be difficult to give you a straight answer.
This article will give you an introduction to spider mites: https://www.gardeningknowhow.com/plant-problems/pests/insects/red-spider-mites.htm