As if those of us glued to a laptop for the last 20+ years haven't already... And yes I have nerd-neck and I wish I could fix it, but I fear it's too late. Despite which, my habits persist <facepalm emoji>.
To be briefly serious, there are basically three colliding things here:
a) posture is dramatically overrated, in general. Having good posture confers few benefits. Would love to see studies refuting this but I'm not aware of any.
b) Posture is a habit. If you change your habits, it will change. There's no magic to it. Just remember to sit straight. If it's uncomfortable... that's just how it is. I don't recommend it. People have been lounging and slouching since we started walking upright.
c) Postural muscles are often weak, so general strength and conditioning can make a big difference in how taxing it is to use your postural muscles often. A deadlift and some heavy shrugs or farmer's carry are often more effective in my personal experience than any amount of reminders and bracing.
Anyway, there's no time like the present to make a change like that, and you're never too old to start. People in their 70s benefit markedly from strength endurance training and calisthenics as long as they're slow and cautious about ramping it up. I don't imagine you're 70, but even if you are, get a doctor's signoff and go nuts.
Bad posture throws off your kinetic chain and forces your joints and muscles to compensate in ways that are not ideal.
For example, anterior pelvic tilt, which usually comes from being hunched over on a keyboard, causes gait problems (since your lower spine is curved more outwards than it should be), which causes additional stress to knees, ankles, and the lower back that can become problematic later in life.
Then there's "tech neck", which happens when your neck is craned downwards towards a device for far far longer than it should be (yay infinite scrolling and endless content juiced for constant micro dopamine hits!). This causes your shoulders and traps to compensate for this unnatural position, which can lead to upper back injuries.
Endemic back problems are basically game over for a comfortable lifestyle. You use your back for EVERYTHING, especially lifting things. Once you have irreversible back damage, your quality of life drops by a lot. Forget running or contact sports, and forget lifting anything heavy. In more serious cases, you can say hello to taking terminal pain meds to do normal light-touch activities that were easy in the past.
But this is one of those things that rears its head at 45, not 25. Kind of like texting while driving (I.e. socionormalized addiction). It's totally chill to text at the red or in traffic because nothings happening...until you hit a car or a pedestrian who crossed the intersection late because you tapped the accelerator out of habit without gathering situational awareness.
From everything I've seen pelvic tilt is pretty overrated as a core issue, same with kyphotic posture and neck strain. Rather than try to directly correct them, it's better to just strengthen the postural muscles. They're symptoms of lack of upper body musculature and neurological recruitment, not diseases.
Most of the reviews of PT literature I've read say "well you can spend a lot of time and effort trying to fix kyphosis/pelvic tilt through cueing, stretching, and bracing but it's not effective", whereas strength endurance exercises indirectly fix it and other issues as well. I'd love to hear more though, I have suffered from both and only was able to fix them with strength training. Ditto low back pain.
