This is a question many people ask. There are a lot of variables to consider but as a general rule of thumb most mattresses might need to be changed every 3-5 years. Especially for cheap mattresses where you can expect to change them during their third or forth year. For higher end mattresses you can expect to use them for many years longer, especially for some of the top of the range memory foam mattress models, like the Tempurpedic mattress range.
Generally you will be able to tell that your mattress needs changing by examining it. If you notice odd formations of springs or the spring feel creaky and old, it is about time you start looking for a new one. Also, the corners of the mattress may sag or there may be a dip where you or your partner have been lying. If you don’t feel the need to go the extent of buying a new mattress, then something like a memory foam mattress topper might be ideal.
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