TRANSITION TIME?

As a collection of regular stamps nears completion, the last few gaps appear to be increasingly hard to complete. A few cheap but elusive stamps seem impossible to find (so why are they cheaply catalogued?); rarities available in Swiss auctions are beyond the normal budget.
Be patient, wait for an opportune moment, but what to do meanwhile?
Many collectors look for an interesting way to move sideways.
Sometimes this would be the "back-of-book" areas of the country you already collect. For instance, if you collect Belgium, the Belgian Railway stamps are a fascinating field, not just for the stamps themselves, but also for station cancels, waybills or parcel documents, station views on postcards. Or, with Belgium, booklet stamps are complex, and many bear attached advertising labels reflecting daily life of the 1930s - the Ostend-Dover Ferry, the Colonial Lottery, and Telefunken Radio in every home.
Technical specialisation is another way : for example, Orange Free State overprints offer countless typographed varieties and settings to explore; Indian States provide more shades of colour than a Farrow & Ball paint chart, Austria's 19th century stamps bear postmarks from Zara to Zwittau in far-flung corners of the old Empire. Hong Kong's Treaty Port cancels are little reminders of mercantile colonialism or the opium trade, but now have become mega-cities with a new name in modern China. There is always history and romance in philately and new fields to discover,
Other collectors prefer to stick to regular stamps, and a sideways move could be literally into a neighbouring territory. For instance, a collector of Italy could explore San Marino, the Vatican, Venezia, Trieste, or the various Italian Colonies. A collector of Canada could visit St Pierre & Miquelon for a morsel of what is almost Canada but with a French twist. For Australia there is a boat trip to Papua, for New Zealand there is Niue, as so on. A collector of German WWII Occupations could extend to those Axis partners like Hungary or Croatia, whose stamps of the war years are not in SG "Germany" but still saw German troops on their streets.
Perhaps you are moving into a transition time too?