During veg I water a couple times with neem oil added in and also do several foliar sprays with it as well. No signs of mites or any other bugs so far.
No, you can get spder mites at anytime of your grow and they will feed from your leaves. If you have a great attention to detail and fairly good eyesight you should be able to notice. Any time you have a bug issue check out the guide to pests under Subcatgorie Bugs - https://www.rollitup.org/bugs/335046-grizzlys-guide-pulverizing-pests.html
during veg , i spray my girls with soapy water and keep a fan on them. I started doing this and I am getting ready to harvest three crops in a row with NO SPIDER MITES. I also grow in rockwool blocks so no soil comes near my crop.