Yes, if you spend several hours a day sitting so your current seat leaves you slouching, tired, or sore, then you should strongly consider replacing it by an ergonomic chair. For a daily comfort and a long-term health, it is one of the simplest upgrades.
A chair's impact must be big for someone to feel a change. Your current seat is likely doing more harm than good when it causes constant shifting. A seat that is lacking in back support or is misaligned with your desk is also likely to be harmful.
Your body knows when a chair isn’t working

If you often feel stiff after you sit, if your shoulders feel so tense, or if your lower back aches now, your chair may be the reason. That strain is removed with an ergonomic chair.
Awkward positions tend to result because of chairs too soft, too firm, or un-adjustable. Tight muscles, also poor posture, in addition to even long-term discomfort result over time. You may think you're just tired at the end of the day, yet your seat may be the real culprit. Your seat is making for your body to work harder than it needs to.
Conversely an ergonomic chair gives support to your body. It helps you stay on track and lessens needless exertion. It also allows for you to focus upon your own tasks instead of discomfort.
It’s not just a new seat, it’s a daily upgrade

Replacing your old chair with an ergonomic one invests in how you feel throughout and after every workday. Week one will likely show the difference.
Your spine will feel more supported so your posture will improve so you’ll spend less time because you will adjust or fidget to stay comfortable. This leads to much better concentration as well as fewer physical distractions. Your body will experience less wear and tear too.
A sign that it is time for a change is if you are already stretching on a constant basis or using of pillows and extra cushions just to make your current chair tolerable. A very properly designed ergonomic chair replaces each of all those workarounds. It gives your body the support that should have existed all along.
Replacing of your chair is in order only if mentally or physically it is holding back you. Your body will be thanked by you.