Learned the hard way years ago. never worried what went down the pipes, septic system only lasted 19 years. In our new home, only 1 & 2 go in the septic, All grey water with soap, grease & all go into a cesspool. 1200 gal tank gets pumped every three years & keep everything cut around the field. Only problem I had, last year I dug the top of my D box up & found the concrete badly crumbling. going to have to be replaced with plastic.

Not uncommon for them to work fine, right up to the day they don’t !

Not what the Septic guys say

One thing for sure. Its hard for two people to overload even a poor system. You can go on for years with two people and never have an issue, thinking everything is ok. Then along comes Christmas or another holiday and all the kids or a bunch friends decide to come and stay over for a long weekend. Most of them think they need to shower twice a day, then all of the sudden there's a turd floating in the tub. Not good with a house full of company. I've been lucky, its never happened to me but I've seen it happen several times to others.

Do yourself a favor, if your having an event that will add a lot additional water, outside the norm of the last few years, get your system pumped or at least inspected. No no matter how long you've been going "without a problem".

You mean the guys that make a living pumping septic tanks?

Good rule of thumb is don't flush anything that won't dissolve in water. In one of my con ed classes for waste water treatment the instructor brought several brands of toilet paper and a gallon pickle jar. Filled jar half full of water and placed 3 squares of each one at a time in the jar. Shook it real hard and then showed which brands would break apart. Charmin was worst of the brands. He said it was great to use as long as you threw it in a trash can and didn't flush it.

Baby wipes have cost sewer systems MILLIONS of dollars in man hours and lift station pumps.
Before I finally put in more leach lines we babied ours for 2 years. Laundry during lot of rain was done at the Laundromat down the road. My system was 28 years old but run off went right across my leach field. Lines should've been in front yard to start with .....

I mitigate this by just not having any company.

Feminine hygiene products are a common problem with plugging septic systems as well. Seems obvious to most folks but if you have girls visit that live in town and are used to just flushing everything into the city sewer lines ...

If I was in the business of installing septic and mound systems, you would be my poster boy.

Nothing could be further from the truth.

Septic tanks are where the solids settle out, then the black water filters through and vertically down through the "drain field", where the black water is naturally filtered in the soil profile.
IF the septic tank is not emptied when it is full, the solids start overflowing into the drain field system (designed to handle liquids only), and in time you will have failure of the entire system.

At this point you will flush your toilet and you'll watch it go nowhere, eventually it will spill over where you prefer it not to.

Yes, septic tanks are where solids settle out, but not to just pile up there until they are pumped out. In a well functioning system those solids are broken down and decomposed by anaerobic bacteria.

You are both right. It depends on how you treat your septic system and to a lesser degree, what type of system. A healthy standard in ground system with a single 1,000-1,500 gallon tank, distribution box and drain field can go many, many years, decades even, without having the tank emptied.

Same with an elevated sand mound system although you need to be more careful with them. You don't want solids getting into the pump tank and getting pumped into the elevated drain field.

An unhealthy system where the bacteria have been compromised from chemicals flushed or one with stuff flushed that shouldn't be would need pumping every 2-4 years depending on how many people are using it.

I'm not an expert but I have installed many of both types of systems and a few aerobic systems as well.