Realistic Time Progression in The Sims 4: My Calendar & Aging System

Last updated 12/5/2025

Hi friends!

One of the most integral and challenging parts of my game and gameplay style is attempting to make time feel real. I want my sims to have time to develop milestones, celebrate birthdays, and experience the ebbs and flows of life changes and grow just like we do.

In this post I’m going to break down my custom aging settings, calendar, and seasons in order to create a realistic sense of time progression so that things feel less rushed.

Whether you’re a storyteller, legacy player, or just want your sims’ lives to feel more natural, this setup might give you some ideas for your own game.

Aging Rules & Lifespan Settings

My sims are going to live forever! Well . . unless tragedy strikes (which is waaaay more likely with lives this long). They at least have the potential to live long full lives and that’s all I’m after at the end of the day.

I’ve always hated the idea of my sims graduating High School and going straight into their “forever” career. Even if they attend university, getting right to work in your dream industry just doesn’t sit right with me.

When I was thinking about extending my sims lifespan, I had to think long and hard about what the trajectory would most often look like for my gameplay.

Sure some ambitious sims might hit the ground running, but more often than not, my sims would end up working in a couple jobs that left them struggling to survive.

I like having the time and flexibility for my sims to change their minds also. Maybe they did know exactly what they wanted to be when they graduated, but now that they’re doing it, it’s not all it’s cracked up to be. Young adults shouldn’t have to have life figured out yet I guess is my point.

And adulthood? Often feels like another looked over life stage. Most adult sims already have young adult children and are well on their way to the grave. Not in my game. Some of them don’t even get started baby making until adulthood.

And how are you experiencing a midlife crisis when you’ve barely lived? It’s ridiculous. Now my adult sims can actually have a true midlife crisis with time to completely overhaul or reinvent their lives before becoming elders.

Elders also have ample time to enjoy the fruits of their labor before kicking the bucket. I almost never had time to enjoy their golden years how I wanted to, because there was only time to “create memories with family”. Bull S***! Now it’s F Them Kids and grandkids if they want. There’s plenty of time to make amends after they complete their bucket list.

Hopefully this bit of context helps make sense of the ages in the chart below.

Lifespan

Life Stage	Sim Years	Days (Sim Time)	Real-Life Age Equivalent
Infant	1	84 days	0–1 years old
Toddler	2	168 days	1–4 years old
Child	2	168 days	5–10 years old
Teen	3	252 days	11–18 years old
Young Adult	5	420 days	19–34 years old
Adult	8	672 days	35–64 years old
Elder	4	336 days	65–90+ years old

The total sim lifespan is now approximately 2,107 sim days! For those doing the math, the 7 extra days is for newborns which I didn’t count since I typically age them up manually anyway.

Pregnancy

Unfortunately, to satisfy the nagging tick in my brain that won’t let semantics go, I also had to increase the pregnancy duration.

That’s right, my sims will be pregnant for nine actual sim months 🫠

I already hate family gameplay so we’ll see how many actually carry this long. I have a strong suspicion I’ll be cheating my female sims into labor but that’s a tomorrow problem.

All negatives aside, most of my female sims don’t even find out they’re pregnant until the second trimester anyway so this really isn’t too too bad. I actually now have plenty of time to plan the things I always want to without feeling rushed or overwhelmed.

AND I can still play with other households while my sims are pregnant without fear of missing any huge milestones #Winning!

Trimester	Duration (Sim Days)	Notes
1st Trimester	21 days
2nd Trimester	21 days
3rd Trimester	21 days
Total	63 days	9 Sim weeks

Calendar Setup & Seasons

I play with LittleMsSam’s 21 day seasons so (in my mind) the calendar breaks down to one sim week being the equivalent to one month in the game. i.e week 1 of summer is June, week 2 is July, week 3 is August, etc.

This makes it easier to setup seasonally appropriate activities. As someone who barely plays with families, I’m really looking forward to my child seems being able to join sports teams seasonally just like I did growing up and my preteens/teens getting to really figure themselves out through multiple attempts with clubs.

I also get to incorporate more holidays into my calendar without being bombarded with a new one every single sim day. We get enough notifications as is and I want holidays to feel fun, not like a chore or burden.

Why I NEEDED A More Realistic Time System

My problem is I cannot play with just one household. I like to be heavily involved in every townies life and even moderately involved in NPC lives.

I also hate how you have to immediately redecorate or find a new place to live once your sims start expanding their family.

As a girl who primarily just likes writing stories and reenacting them in the way, all the other tedious task like building and decorating tend to take me a long time. The problem with taking your time decorating is your sims lives change too quickly to enjoy all the hard work.

Why on earth would I spend hours customizing a home just for the sim to want to get married, expand the family, or die 2 hours later? Nah bro. I can’t have that. They are going to enjoy their space for a long time whether they want to or not.

It’s also a big part of the fun for my sims to be able to grow into their spaces. Having ample time to fix up and really tailor their homes to their personality as they evolve is so satisfying. I wasn’t doing any of these things before and found the game quite boring as a result. Now I can play in a way that doesn’t stress me out and instead leads to be sitting at my desk for hours at a time. 🙃

Conclusion

Is this brilliant or the dumbest decision I’ve ever made? Hopefully I’ll stick to one save file long enough to find out. I’ve always enjoyed slow gameplay so, for now anyway, that nagging tick in my brain has been silenced, and I’ve been able to enjoy playing my game more than ever before.

What age setting do you play your game on? Do you use custom age settings? I’d truly love to know; especially if you play on short lifespan. How do you do it? Just the thought of that gives me anxiety lol but leave a comment below and let’s chat it out.

That’s all for now friends!

Stay Kind, Until next time 💋