Regular checkups are vital for long term health. This applies to animals as well as humans.
A visit to the vet was prompted by an unusual frequency of vomiting. It isn't unusual to vomit hairballs, this is even considered healthy cleansing of the food ducts. However, excessive vomiting and reduced appetite can lead to extreme fatigue and potentially death.
A visit to the vet and a full blood examination will ensure no serious problems are brewing under the hood.