Whatever you decide on, ideally you want to aim for it looking better than showroom, lol.
lol
From what I can gather -
WAX = the more prep the better the end result, easy to use, good results, needs to be applied 2 or 3 times a year.
SEALANT = the more prep the better the end result, easy to use, not as glossy as wax, only needs applied 1 or 2 times a year.
Prosumer Ceramic Coatings = paint needs full decontamination and preparation, must be applied carefully following instructions, will last 1-2 years
Professional Ceramic Coatings = must be applied by a detailer (requires sanding off if improperly applied 
) will last years.
As it is a new car I was considering applying something like Gtechniq Serum Light. However, I imagine that tar will stick to anything. Therefore, the car is still going to need a good clean summer and winter. Though will a quick rub down with tardis be all that is required?
Regardless of the choice of protection, good prep and careful application is the key. If you are applying a long life coating, a full decontamination prep is an absolute necessity otherwise you will be sealing in contaminants. Car should also ideally be machine polished to remove any swirls first, otherwise, again you will be sealing these in.
WAX - it varies depending on the wax you use, but IMO a more realistic estimate - application every 3 months at best.
SEALANT - again depends what you choose as to longevity, but some sacrificial sealants such as Gtechniq C2v3 require more regular application than 1-2 times a year, much like wax.
Remember with both wax and sealants (and quite possibly, coatings), manufacturers overstate the lifespan, sometimes greatly, a bit like VW with mpg figures, lol.
Professional Ceramic Coatings - it's really only likes of Gtechniq Crystal Serum that can only be removed by wet sanding, many other coatings (pro applied) can be removed by machine polishing.
Coatings will repel contaminants to an extent, but ultimately over time, tar, sap, iron/fallout deposits will embed themselves into the paint and will need to be removed a few times a year by proper full decontamination process - de-iron; de-tar and possibly claying.
