Having a few good kits is a good way to get a wide assortment of values but only maybe 10 or 25 of each.
For the more commonly used values I don't see a big advantage of buying full reels since for cheap passives like resistors the reel capacities are often at least 2500 pieces, sometimes 3000, 5000, or 10000 pieces. Although that may be a lifetime supply, as has been said, there are also concerns about the lifetime longevity of the solderability, the tape adhesive remaining fixed to the reel, and bulky storage, and so on that make it less convenient and more risky to have reels you expect not to use for more than 10 years.
For resistors and cheap MLCCs I find that the price to buy cut-tape quantities of maybe 100, 250, or 500 pieces is good enough that I can just get such quantities instead of a reel of 3000 at once and be happy to have enough for a year or a few in many cases without the cost and storage overhead of having a couple of dozen reels around.
That said sometimes I'll buy reels or partial reels from surplus places for certain components if the prices or compoents are particularly attractive but it is still easy to waste money buying more than you will need in a few years of a certain part so often it is better to just buy by the dozens or hundreds. I still have surplus through hole components that I'm less likely to use in the future due to obsolescence because I bought too many at once thinking to get a "good deal" not thinking that in 5-10 years the technology would change so much they would not be very useful.
But if I would buy reels I'd get authentic / non-counterfit parts from suppliers like:
Vishay,
Kemet,
Murata,
Bourns,
AVX,
NXP,
TI,
Johanson,
Laird,
Wurth Elektronik,
Panasonic,
Susumu,
ON Semiconductor,
International Rectifier,
Diodes Incorporated,