"Auto detailing is an activity that keeps the vehicle in its best possible condition, especially cosmetic, as opposed to mechanical. This is achieved by removing both visible and invisible contaminants from the vehicle's interior, and polishing the exterior to its original blemish-free finish."
~ Wikipedia
That's the official description from Wikipedia.org, but there really is a lot more to it than just that.
What Detailing Really is.
Imagine doing a valet on your vehicle, for 3 to 6 hours, while on a double dose of Ritalin.
That's what detailing really feels like.
It requires a ton of experience, skill and know-how to ensure that you do not damage the delicate parts of the vehicle, or knowing what to do in order to not introduce additional scratches, swirls and holograms to your vehicle's paint work while hand washing - as is normal at your local "wash-n-go" carwash, or knowing that you should not be using Sunlight dish soap when doing your diy at-home hand wash (shame on you). It's about knowing what to use, when and where to use it, when to extract, what you can and cannot steam, and what to do to get in to those tight crevices and corners between your air vents or behind your exterior accents, without damage or leaving behind dust that would later cause off-color drip marks on your paint work after the first rain fall.
Professional auto detailing requires special attention to detail in order to ensure that every nook and cranny is spotless, whether the customer will notice it or not, and it requires a lot of really expensive equipment and specialized pH balanced cleaning solutions, to prevent damage to rubber and plastic trim. Unlike the "diy Sunlight guy", a professional detailer will know that such a chemical is a degreaser, and a degreaser will not only remove all the dirt from your paint work, but it will also remove any and all wax and ceramic based protective layers previously applied to your paint work, which are specifically designed to protect against harmful UV-rays and ultimately result in your vehicle looking old, faded and dulled.
A professional vehicle detail is a time consuming process, it's an expensive process, requires an expert touch and it's the only process that will keep your vehicle immaculate and looking sharp.
It really depends on your requirements.
What is your personal requirements;
- Is your vehicle a daily runner, transporting 3 kids and requires a really good decontamination and extraction to remove all that stickiness, or is your vehicle a "weekend show piece" that you want to keep in an immaculate state for when you go golfing over the weekend, wanting to show off your shiny sports car;
What's the state of your vehicle;
- If you haven't washed the thing in like 12 years, there's really no amount of detailing that could restore it's "original beauty". However, if you recently purchased it brand new, it's always a good idea to keep the paint work protected and scratch free, to prevent fading and dulling, and retain as much value as possible over time;
Are you planning to sell your vehicle;
- There are many articles, studies and videos all over the internet that prove that properly cleaning your vehicle, before attempting to sell it, could drastically increase it's value when you take it to the dealer, or sell it off hand;
Did you recently purchase the vehicle;
- ... Secondhand ... from a 'suspicious character' ... with cash ... behind the laundromat, and you would like to 'decontaminate' the thing. Detailing your recently purchased secondhand vehicle helps to remove any old stains and scuff marks (possibly blood or alchohol - "allegedly") that the previous owner may have left behind and makes it feel like a "new car". Most car dealerships will go through the effort and expense of a professional detail before reselling a vehicle to you.
These are some of the factors that will ultimately determine whether you should or should not go through the expense of having your vehicle detailed by a professional, and only you can determine if it's really necessary, or within your budget.