I was telling @tony that my guitar wasn’t staying in tune and the intonation wasn’t right. He sent me this video and in it I find the solutions to my problem. Thankyou Tony 
@jkahn you have a doppelganger.
There’s also this illustrated script.
https://guitarrepairers.com/how-to-restring-your-guitar/
The knot is key to the strings not slipping.
The other option is to fit some locking tuners.
I don’t knot the strings, and my acoustic doesn’t have locking tuners. I follow the way this Taylor video teaches and I never have problems with the strings slipping. The guitar stays in rock-solid tune.
If you do it as per batwoman’s post, you’re essentially creating a half knot over and through the post, where the string not only locks itself on the capstan, it also overlaps and clamps to give a bit extra security.
The Taylor method simply relies on the string locking against itself on the capstan (two wraps on a suitably curved capstan should be enough for the string to lock - this is the principle used on capstan winches for ropes)
It does work, but there is a bigger risk the string can slip, especially with the unwound strings.
Perhaps, but it’s never happened.
I’ve been using the Taylor method and this is the problem.
I suppose a lot depends on the design of the tuner posts on your guitar(s) and the gauge/make of the strings.
I’ve used both the ‘Taylor’ method as shown above and the ‘knot’ method. They both work for me and if I ‘stretch’ the strings to bed them into their windings I don’t suffer from slippage using the ‘unknotted’ method.
On a side note, I always wince when I see people using side cutters to remove a tight bridge pin. I put my hand into the sound hole and using the flat surface of a coin I push the pin out from the inside. That way you don’t risk marking or damaging the bridge.
I use a plastic pin puller for that same reason. The sharp metal jaws of the side cutters too likely to cause damage.
It helps perhaps, not convinced, what it really does do is making removal of the strings a pain.
Never done it, never felt the need.
Snip/slacken string, unloop from post, and pull through hole.
The only additional thing is an extra bend so the string doesn’t fall out the hole, unlike the Taylor method where the string pretty removes itself as soon as you remove enough tension.
@batwoman I would never wear overalls… 
Strangely enough, I’ve never had my guitars go out of tune from strings slipping. They do vary with the weather (humidity/temperature) but that’s expected.
I don’t have locking tuners either. Just string them the way the fender videos showed.
I restring my guitar as recommended in Justin’s video and never had any issues with slipping strings or tuning problems. As JK mentioned, only smaller adjustments due to weather conditions are neccessary. Apart from that, my guitar stays in tune for a long time.
I’m very careful to loose tight bridge pins as once, I broke the saddle while trying to lift the pin with the string cutter tool. Now I’m doing it like sairfingers and put my hand into the hole to lift it.