Boots are your most important equipment and should last you the longest. So pick them with care, within your atheletism (with room for skill growth). And within your budget.
For beginners boots should be above all comfortable & flexible. Or your skill acquisition will be hampered.
For every skier level you should try on the boots in the shop for at least 30m stomping and flexing to see if you have loose connection in the heel pocket and any pressure points due to bunnions etc. Todays boots and liners are pretty good in terms of heat formed customization - to make them a wee bit larger/not smaller.
Initial put on fit should be snug - with your toes able to wiggle but not able to slide around at all - your heels locked in. Any good shop will measure you up to see what boot with what last (width of the fore foot) will be best for you.
Ditch the ego and avoid the sales pitch. Dont buy up to snazzy looking stiff boots way above your ability.
For not very athlettic, out of shape beginners go with a beginner / soft boot. If you are overweight then you may in rare cases need to move up to a stiffer intermediate boot.
For an athletic beginners (skates, roller blades, water skis, etc) do consider a intermediate boot, this will give you room to grow as you will likely advance quickly.
Choose a flex rating of 90 or less soft boot (yeah we can debate about brand uniqueness etc etc - the Germans should come up with a DIN std). When you try them on in the shop you should be able to flex forward and crush them when fully buckled up. In the cold the boots will get a lot stiffer.
If you have typical even wide feet then heat forming should address any foot bulges etc. Stick & glue on and taped filler pieces on the liner such as heel keepers should address any extra narrow / low volume areas of your feet.
If in the rare case you have hobbitt feet then a boot fitter + the extra bucks maybe required.
For beginners and most intermediates a boot fitter should be the last resort, it can be expensive and sometimes hit or miss. For advanced to experts & professionals a good boot fitter is often the starting point unless you have experience with what works for you or have some basic boot fitting experience.
GL
