Welcome, and thanks for doing your research before getting a frog! If the dubias are the only reason you would be waiting that long, it's worth mentioning that they can live fine on a staple of nightcrawlers with occasional pinkies or frozen/thawed silversides as treats. Variety is good for them though.

If you keep the frog in proper conditions, a vet usually isn't necessary. About the only problem I can think of that is common even in healthy pacs is impaction, but the treatment for that is usually just a soak in warm water with a few drops of honey in it.