My daughter's boyfriend graduated basic Sept '17, went to SD for A school right after that. He was there until Feb '18, then got orders for his duty station in the state of Washington .  From what she's experienced, they can be deployed for months at a time.  His last deployment was 4 months.  They see each other about 2 times a year. However, with technology they communicate every day. 

It depends if he signed a 4 year or 6 year contract. My husband had a 6 year contract and therefore was in San Diego for 2 years for A and C school before going to his first duty station. He did deploy right away, in fact his first duty station was in Norfolk, VA and he deployed so soon after that we made the decision for me to stay behind in SD until he came home. This was 2013 and he has deployed 2 more times since then. In between the long deployments (which for him, have ranged from 6-12 months), he can be gone up to a month at a time doing training to prepare for deployment. Communication is much better now than even his first deployment in 2013. We have been able to talk almost every day his last 2 deployments. When he is not deployed, he goes to work and comes home at night. Honestly, there is really no way to understand until you are living the life. No matter what anyone tells you, every experience is going to be different because every ship makes it owns rules. For example, my husband's second ship had people on it who had never deployed before but had been in the Navy as long as him. He has now been in for 8 years and is at his 3rd command, and there are people who have been in the Navy longer than him and have never deployed. All STGs. You just never know.