If you have DSL, never upgrade to FIOS. First, they won't let you go back if you aren't happy with it. So if you don't like a 65% increase in non-contract prices and paying $45 for batteries that go out once a year..... too bad. Don't fall for the bundle prices with all of the hidden fees - you will have a major increase in price going from a land line to Fios.
And once they get you, you can't even get the simple non-contract services & prices they would offer to someone should they move into your house. Ask someone at Verizon for some clarity on what prices they charge - it keeps changing based on who you are and never works out for repeat customers. Just go on-line, ask for a price quote as someone moving into your current residence, and you'll be shocked.
Verizon doesn't care at all about retaining customers just locking them into higher priced services (that offer negligible benefits over the prior service).
And if you really want to upgrade to Fios internet - avoid the TV at all costs. Installation will try to install old equipment, support will spend hours telling you how you can fix it on your own, and billing will tell you to pay for services incorrectly installed. And to top it off, the controls and features are flat out completely behind what others provide.
You're name has Texas in it so I take it you are in TX? Frontier will be taking the state (FL and CA as well) over at some point in 2016 so if you really don't like things now, just wait. I heard Frontier is horrible.
I've been with Verizon since 2009 and have been happy myself, but am worried about Frontier.
If you have DSL, never upgrade to FIOS. First, they won't let you go back if you aren't happy with it.
I upgraded from DSL to FiOS many years ago. It's been great. At the time, there was no cost difference between DSL and 15/5 FiOS and they gave me a gift card. I've since added TV service, a 2nd phone line, 75/75 service and upgraded to the latest router. It's all good.
One thing I learned about Verizon back in the DSL days is they almost never let you "go back." If you're on a plan that isn't offered anymore, you won't be able to get it back if you switch off it, even for an hour. Every Verizon customer should understand that and be very careful when making changes that involve "grandfathered" plans. The alternative is they kick us off these plans when they stop offering them; so I'll take the approach they use.
DSL is a special case, as copper is turned off for good when FiOS is installed. I was worried about this when I switched, but it's turned out to be a complete non-issue. FiOS is technically better in almost every way than copper. I'm glad I switched.
Verizon, like every other provider, offers teaser rates to new customers. Existing customers can not get those rates. The only way to stay on a teaser rate is to switch providers every few years. Each person has to decide if the process is worth it to them.
For me, I've ended up "out of contract" with Verizon. I routinely call and get a "valued customer discount" that keeps my costs at a level low enough to keep me from switching. Verizon is very good at knowing just how low they should go. If you do this, be sure to call their retention team as they often are able to make the best offers.
You also mentioned batteries. The FiOS ONT uses a battery to provide power for phone service during outages. Verizon has been clear since day one that the battery belongs to customers; although they used to give us the first one for free. Batteries can be purchased for much less online or at local hardware stores.
The battery is not used to power Internet or TV. Internet only customers don't need a battery. Depending on the model of power supply, the battery can be left out without any annoying alarms.
Lately, Verizon isn't providing any batteries for phone backup. They sell an expensive box that takes a bunch of D-cells (not included, of course). It provides the same phone only backup function as the rechargeable battery used before.
Many folks, myself included, use a small UPS to power the ONT. This keeps Internet up during outages. Since FiOS is a passive optical network, it usually stays up as well since it doesn't have any powered equipment in the field.
You're right about the 'never get to go back'. Too bad their sales people don't tell customers.
The problem at least in Texas is the battery packs are put in the garage and while the batteries are supposed to last for years, batteries don't last nearly that long in the Texas heat. And then the beeping starts (and can't be undone by just unplugging the battery).