Most of the time, calling your vet about a worry is going to be more helpful than posting online about whether you need to see the vet. If you have a good client relationship, they will nearly always be glad to talk by phone to help you figure out if you need to come in. If you don't, and they haven't seen your dog in forever, they have to tell you to come in.
If you have a Home Again microchip and pay for their annual "premium" membership ($17, last I checked), the premium service gets you unlimited 24/7 access to an emergency phone line staffed by a licensed vet. The phone service is EXCELLENT -- I used it when I had that membership, and I liked it a lot -- when the dog vomits in the middle of the night, they can walk you through the decision-tree of whether it's an emergency. They also have access to the poison control database.
If your dog ate something it shouldn't have and you don't have Home Again, in the U.S., you can call the ASPCA's Animal Poison Control: (888) 426-4435 -- it's a $65 fee charged to your credit card, but they can calculate whether the amount eaten of just about anything that is potentially toxic based on your dog's weight, and tell you whether you need to induce vomiting immediately (or not), administer activated charcoal (or not), etc.
ETA: I understand not having a long-term vet relationship because of cost -- I remember being young and poor, living on student loans, and chasing coupons and specials for annual preventative care to save money. I think that the lack of a good vet relationship in my early 20s probably shortened the life of a Doberman I loved dearly. She died of an undiagnosed heart issue that wasn't picked up by a vet during any of her annual visits. I think they missed it during her annual exams because she never saw the same vet for those visits. It was always someone new. I had no long-term relationship with any clinic as I thought we were just doing basic preventative care on a healthy dog. We just went where it was cheapest, if we needed to see a vet. The dog got a quick, routine exam, and that was that. I'm very sure that the excellent, careful vet my dogs see now would have picked up on the anomaly and referred me to a vet cardiologist -- seeing the same perceptive, careful vet several times a year means he picks up on very subtle things because he has a chance to spend a lot of time getting to know them and their "normal." Exams take a while, with that level of care (and also cost more than at high-volume/discount clinics). We missed out on that kind of vet relationship when we were vet hopping, when we were very young, unfortunately. For the young people reading and learning, please try to invest in building a relationship with a good vet -- your dog's care will be better over its lifetime, if you have someone you can trust who's totally invested in good outcomes for you.
Last edited by Magwart; 12-28-2018 at 02:55 PM.