Create a maintenance and replacement plan

It varies too much for a general figure to be useful: the material, the tooth, the bite, grinding, and how well the margin is kept clean all matter. Any number quoted without those caveats is close to meaningless. The more useful questions are what would shorten it in your case, how a problem would be detected, and what the plan is when it needs replacing.

Because the junction between restoration and tooth is where bacteria can get in. The tooth can decay beneath an intact restoration. This is why a crown is usually lost to the tooth beneath it instead of to the crown itself, and why cleaning around margins matters as much as it does. It is also why the examination at a maintenance visit matters more than the cleaning.

Different instead of uniformly more. The assumption that they need less is the dangerous one. Implants cannot decay, which people take as meaning less attention is required. But the bone and tissue around them can be lost to peri-implant disease, which is silent early and detected by probing and radiographs on a schedule of its own. That monitoring is not optional.

Identify what has a defined service life, what the wearing components are, and spread an estimated replacement cost across the years, not treating each event as unexpected. Ask the practice what maintenance and servicing typically involve for your specific work. Doing this before choosing between treatment options also makes the comparison between them more honest.

Not necessarily: a warranty is a commercial guarantee about replacement or repair terms, which is a different thing from the material and biological factors that actually determine how long a restoration serves, so a longer warranty is worth having but shouldn't be read as a prediction of durability; it's more useful to ask what specifically the warranty covers and under what conditions it applies.

It can be, if there is a specific finding, decay developing at the margin, a crack, wear that has changed the fit, visible on examination or radiograph even though you feel nothing, since many of the processes that end a restoration's service life are painless in their early stages. It's reasonable to ask what specific finding is driving the recommendation instead of accepting 'it's old' alone as the reason.

Some components allow targeted replacement of just the worn part, a retention insert in an overdenture, for example, not remaking the entire appliance, which is generally faster and cheaper than a full replacement; whether your specific appliance allows this kind of partial servicing is worth asking about directly instead of assuming full replacement is the only option when something wears.

Yes, significantly: a new grinding or clenching habit places forces on restorations, implants and natural teeth that they weren't necessarily designed to withstand long-term, which is exactly why a night appliance is commonly recommended once grinding is identified, specifically to protect existing investment in dental work instead of just future work.

A reline resurfaces the fitting side to match a ridge that has changed shape, a repair fixes a specific break or crack without addressing the whole appliance, and a remake starts fresh where wear, repeated repairs, or bite changes mean the existing denture can no longer be brought back to a good fit. Which of these applies to your specific denture is a judgment your dentist makes at examination, not something to guess at home.

Keeping your own copy is worthwhile insurance even though the practice is also required to maintain records, since practices close, records can be lost in a transfer, and having your own note of key procedures, especially implant system and component details, means you are never solely dependent on someone else's record-keeping years later.

This varies considerably by plan and by the specific maintenance item: some ongoing care like periodontal maintenance visits may have their own benefit category, while component replacement for something like an overdenture attachment is often excluded even when the original implant had some coverage, so checking the specific maintenance item against your plan's terms is necessary, not assuming continued coverage.

Keeping a simple written or digital log noting each restoration or appliance, when it was placed, and its specific maintenance interval is a practical way to avoid losing track once you have several items with different schedules, and asking the practice whether they can provide a summary of this at each visit is a reasonable request that saves you reconstructing it yourself.