Actually, if cost efficiency is what you are really after, then most would say don't buy anything at all within the first 5 years of being released. Most sets never hold on to their original cost as a true value. Therefore, overall even ifan odd set does eclipse the original cost,in the long runyou will be way ahead money wise if you purchase sets long after they are released. Before you make a silly counter argument, this is meant about sets released since1985 or there abouts.
That argument set aside, nubula, collect for the love of the hobby, which ever way you most enjoy. Most of us on here do it exactly in the way we wish and respect all others in their own ways. Remember it is a hobby and it does not put food on the table or a shelter overy our family's heads.
Bruno
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Check my Profile page to see my 2023 Goals and my Lists of sets near completion (5 cards or less) or sets getting close (less than 100 cards missing and 75% complete).
https://www.tcdb.com/Forum.cfm/Page/B/ID/0/?MODE=VIEW&ThreadID=25745&C=0