Swirls are pretty common on paint and can be easily identified, they look like a spider web and radiate out from a central point, they are usually more visible on dark coloured paint and especially in bright sun light or under filling station lights at night. Swirls look terrible, they take away the gloss and usually cover the entire car. But they can be safely removed as they are usually shallow and only in the clear coat. It is simply a matter of polishing them out, however its better to try and avoid getting them in the first place.
Hazing is a patch of dull paint, typically this is caused after compounding to remove other defects. Compounds tend to contain a lot of fillers and if not removed by a good panel wipe will hide defects until it is washed or wears off. Hazing can easily be removed by a finishing polish and is nothing to worry about.
In short a wax is a naturally occurring substance and a sealant is man made, people say wax produces a wet looking shine, this is due to the oils that have been added to it in the manufacturing process.
A sealant will better show off any metallic flakes in the paint and is longer lasting.
Both of these products contain fillers and tend to be used by people to mask poor polishing and paint defects.
They are both quick and easy to apply.
If you imagine it like this, a girl going out for the night puts on makeup and looks great, after she comes home she washes her face and looks the same as she did before putting on makeup. That is a valet, we are in essence applying makeup (products containing fillers) to the paint to hide the scratches and swirls and produce a shine. These will gradually fade/wash off over time usually a couple of months and you will be back to square one.
A detail is like a girl going for cosmetic surgery and getting a chemical peel where the surgeon removes a layer of skin exposing a fresh layer and she looks great for a longer period of time. The detailer machine polishes the paint removing a microscopic layer so the swirls, scratches, oxidization and marring are removed.
This depends on a number of factors, service chosen, size of car, colour of paint and condition of the vehicle. It may not be obvious but if you have dark paint e.g. black and want it detailed you should chose a two stage machine correction, however if it is light coloured paint e.g. silver a single stage correction would be fine. This is because the marring instilled from the compounding stage where we are correcting the swirls and scratches will not be visible on light coloured paint.
The real question here is how long will it take for you to mess it up? Our cars don’t live in a bubble they are for the most part driven on the roads so they get dirty, birds poo on them etc. resulting in possible damage. The paint will have to be washed, your technique products and equipment needs to be good otherwise you will mar the surface. If you are worried about surface marring have a look at ceramic coatings which provide a better shine and protection against UV and acid damage and surface marring.