To check the fluid levels on your car you seldom need anything more than your eyes, and a lint-free cloth, or sheet of kitchen roll (to wipe the oil dipstick before taking a measurement).
There are tools involved in changing fluids, but cars are designed so that you can monitor the fluid levels without having to get the toolbox out.
If you check the oil and it is low it's wise to use a funnel to help top it up (it can be a very messy business otherwise!). But other than that no tools are required.
In simple terms you should never exceed the manufacturers recommended service intervals. Over time oil and coolant can degrade and their performance and ability reduces.
Not adhering to service intervals can decrease the reliability and life expectancy of your engine, so it's simply unwise to seek out a way to extend the life of your fluids.
With the advent of modern oils and additives, engine oil and coolant lasts longer than it ever has – but that doesn't mean you should ignore the service intervals.
It's generally recommended that you change your oil at least annually, or every 10k miles, whichever comes first. Although some manufacturers state shorter, or longer intervals between changes.
Coolant generally has a much longer service live with some manufacturers recommending a 15-year, or 150k mile change! Although a shorter 5 years or 50k mile interval is a more common recommendation.
With both of these fluids it's important that you consult your handbook, or ask you dealer to find out the correct intervals.
Depending on your car, and how much oil it uses the price will vary but for an average car (such as a Ford Focus) an oil filter (which you must always change at the same time as carrying out an oil change) will cost you less than £10 and the oil will cost between £20 and £50 depending on how posh the oil of your choice is.
The same job at a dealer is likely to cost you up to £100 depending on their hourly rate, so you can see that there is a considerable saving to be made.