When you are choosing a mattress, you  may wonder which mattress option is best for you. Though many of us spend a third of every day in bed, we only find that we all prefer a soft and warm bed and have no idea what is suitable for us. Actually, it is important to find a mattress that can support your body in a right level. Getting your mattress firmness right could be just the thing to help you get the most restful sleep. 
Normally, there are three kinds of firmess mattress frequently sold in the market--Soft, Medium and Firm Mattress.  Anmiz mattresses are medium firm mattresses. A simple way to indicate them is lying on them and see how much they sink.As their names suggest, soft mattresses sink more than medium mattresses, while medium mattresses sink more than firm mattresses.
Now you may wonder the pros and cons of each firmness level and what's best for you?  We’ll take a look at those questions.

Soft Mattresses

Soft mattresses have the least resistance to weight and pressure, deforming easily. Whether or not the level of deformation is suitable for you depends on how much you weigh because this dictates the sinkage level.
Generally, soft mattresses are suited to people weighing under 130 lbs (9.2 stone) and people with arthritis or joint pain.
If you weigh more than a soft mattress can support, you will sink deep into the bed, knocking your spine out of alignment and crumpling the mattress edge. You might also get roll together, where the mattress dips in the middle. The best sleep position for soft mattress is side sleep.

So if you are a side sleeper who are under 130lbs with arthritis or joint pain, the soft mattresses are suitable for you.

Medium Mattresses

A medium mattress responds to pressure with body-cradling give, but it also offers good support. It may also have more responsiveness than a soft mattress, springing back slightly with pressure or movement. For many, a medium mattress offers the perfect balance between too soft and too hard. Average-weight people who prefer to sleep on their back or side may find a medium mattress provides just the right amount of give for their hips and shoulders while helping to keep their spine supported and neutrally aligned. And for couple It’s a no-brainer! When one person wants a firm mattress and the other prefers something softer, a medium to medium-firm mattress can satisfy both preferences.
ANMIZ Mattress may be a perfect chioce if you want medium-firm mattress.
However for many, a medium mattress hits the sweet spot between comfort and support, but there are some disadvantages for the lightest- and heaviest-weight sleepers. 
Lighter-weight sleepers may need a softer mattress with more give to cushion their pressure points. Medium mattresses are best suited for average-weight sleepers.
A medium mattress may not be quite supportive enough for some heavier-weight sleepers. In general, the heavier you are, the firmer your mattress should be. Consider opting for medium-firm or firm instead.
So If you’re an average-weight sleeper and sleep on your side or back, a medium mattress is an excellent choice. It’s also a great compromise for couples with different firmness needs.

Firm Mattresses

For most sleepers, a firm mattress feels as though you’re lying on top of it rather than settling into it. Heavier-weight sleepers will find they are better able to move on a firm mattress without feeling “stuck.” The best mattress for you depends on a few variables.
Here are some of the advantages of a firm mattress:
Well-Suited for Stomach Sleepers
If your idea of comfort is sleeping on your stomach, a firm mattress may be the best choice. A firm mattress is less likely to give, which can prevent your torso from sinking and help keep your spine aligned.
Provides More Support for Heavier-Weight Sleepers
Heavier-weight sleepers may want to opt for a firmer mattress. Some find that softer mattresses sink, which can cause uncomfortable spinal misalignment. A too-soft mattress can also restrict circulation for bigger-bodied sleepers.
Here are a few reasons that you and a firm mattress may not be the perfect match:
Creates Pressure Points for Side Sleepers
If you’re among the majority of people who sleep mostly on your side, a firm mattress could be uncomfortable. Its lack of give can create pressure points, especially around your hips and shoulders. 
Uncomfortable for Lighter-Weight Sleepers
Lighter- and average-weight sleepers may find a firm mattress too hard. The smaller and lighter you are, the less a firm mattress will contour to your body in a way that feels both supportive and comfortable.

So If you’re a heavier-weight sleeper, choose a firmer mattress for the best overall support. Also consider a firmer mattress if you’re primarily a stomach sleeper.