Hi kchurch2213,
While there is no way to specifically quantify how long any mattress will last for a specific person or predict exactly when they will decide to replace it because it is no longer suitable or comfortable for them (because this is the only real measure of durability or the useful life of a mattress that really matters) and because there are too many unknowns and variables involved that are unique to each person … if a mattress is well inside a suitable comfort/support range and isn’t close to the edge of being too soft when it is new (see post #2 here) and you have confirmed that it meets the minimum quality/durability specs relative to your weight range that are suggested in the guidelines here then it would be reasonable to expect a useful lifetime in the range of 7 - 10 years and with higher quality and more durable materials like latex or higher density memory foam or polyfoam (in the comfort layers especially) it would likely be in the higher end of the range or even longer and the chances that you would have additional “bonus time” beyond that would be higher as well.
There is also more detailed information about the variables that can affect the durability and useful life of a mattress (and the materials inside it) in post #4 here and the posts it links to as well.
If you were only talking about a single layer then I would give latex the advantage vs 5 lb memory foam in terms of durability and any additional “bonus time” you may experience but with a mattress that includes multiple layers and when you are looking so far into the future where there are so many other variables and more subjective considerations involved that can vary from person to person such as the loss of comfort and/or support relative to the comfort/support range that would be suitable for any specific person then it’s impossible to know for sure when it comes to a specific mattress design.
The Ultimate Dreams Aria has 4" of 4 lb memory foam which includes thicker layers of 4 lb memory foam than I would normally suggest in your weight range which would be more risky in terms of durability than either of the other two mattresses.
Phoenix