Maintenance logs... How do you keep track of services?

Every single thing I do to any of my vehicles gets logged into a spreadsheet. Included is date, miles, work done, part with number, cost and comments if needed. EG: lifetime warranty on shocks or brake pads along with where I bought the part. Invoices for parts with a LT warranty are in my file cabinet. In the rare event a shop does the work I name the shop. I have spreadsheets dating back to 5/7/88 when my 88 E-150 got it's first oil change with 1,000 miles on the clock. Older vehicles were deleted. I had written logs in each of the vehicles I owned which I kept on a spreadsheet when I bought my first PC.
I log the info on the Kia dashboard online and I also keep all receipts for parts or any services performed by a shop and I have a written maintenance record as backup. I've done the same with multiple vehicle manufacturers. If it is an older vehicle I just keep receipts and written records only. Not super detailed. The written book just has check boxes for different services and a small space for notes. If it's a new vehicle, I like to keep the window sticker with my records too.
For a while I kept both a paper log and a file on my computer but then I got lazy and now just use the car fax app. It’s easier because most everything I buy for the car is from online so I can just screenshot the receipt and upload it to car fax. I use it to track my mpg too.
Whether using a spread sheet or paper log, I don't waste my time duplicating the info on the saved/scanned receipt (brand, part no., cost, etc.). I don't do cost analysis of ownership like a fleet might. Rather be out fishing.
This is better than what lots of poeple do (nothing) but why bother to use a computer, but not be consistent with times, pricing, dates, hours of time etcetera? You are missing costs, work times and cant come up with total for either based on this.

What does - OEM 45K mile suspension 130K - mean?

I use vehicle logbooks that then get passed on to the new owner when I sell the vehicle and I keep scans of major work.
When i get to the bottom of a work page in a book I tally the page and start the following with the dollar entry with the total from the prior.
Here’s the full story, and I’m sticking to it. 😂 I could put: used OEM 45K mile SX suspension from a 2012 koup installed at 130,000 miles $xx

When I picked this car up, it was lowered or I would go as far as to say, slammed and figured an OEM lower miles sport suspension would be better than taking a gamble on an aftermarket set up.

I know what every single piece of information on the short hand maintenance log means and that log is just for me and not the next owner.

If I ever do sell the vehicle, they will get the short hand maintenance log with the paper receipts.

The physical paper of all the receipts labeled with mileage dates times prices part number, etc. and it’s also organized from oldest to newest dates/miles and it does correspond to the digital shorthand maintenance log

The picture of the short hand maintenance log is just realistically a “rundown”

Also I have the prices for every single part I have put on this vehicle and could add them up and break it down, but it makes no difference to me and the same goes with fuel - I just assume expensive and leave it at that.

I use a spreadsheet with mileage, elapsed mileage (used for oil changes), date, service type, and comments. The comments section is quite useful - how dirty was that air filter, did the plugs look good, etc. I keep the receipts in a paper file.

I have a separate section listing all the routine service types with: recommended mileage or time interval, next mileage or date when that service is due. I highlight this year's service needs in red. Helps with the organization.
I write it in a notebook and log it online on the Honda Owners site....
I use 3x5" notebooks in the glovebox of each vehicle. I write down date, mileage, parts used and part numbers if applicable. I also write where I bought it and if it has a lifetime warranty.
Tracking oil changes I use this thread:

For personal vehicles I use MS Excel with part type, part number, date/mi performed, price and where I bought the part.

For non-personal vehicles I type out a work order consisting of driver complaints, observed issues, parts needed to perform repairs, repairs performed, and miscellaneous info.
I’ve used excel in the past, but started using the Fuelly app about 2 years ago. This does have issues.

Since I use the free version, when I accidentally deleted my Camry instead of the VW, I lost all of my records. Thankfully it was only a battery and 1 oil change.

So, the risk is the app goes away, but, the ease of use makes it worthwhile.

I may keep a spreadsheet for my Rogue as a backup since it’s under warranty. I’ve also considered the dealer changing the oil while it’s under warranty as well, but still logging in fuelly.
I have to research this.

Wow, that brings back memories. I used to do that on the AOL software days.
Oh and Toyota, Lexus, and Kia all allow you to document service on their owner's websites.

The owner's websites do not let you upload receipts but AUTOsist does - I keep both the ower's website and AUTOsist updated.
I use the “My Mopar” app. Even let’s you add notes and select maintenance categories.

Been using the same Excel spreadsheet since January 27, 2004. At least a dozen tabs (one for each vehicle) across the bottom.

When I sell a vehicle, a printed copy of that vehicles tab goes with the vehicle.