I've been interested in my hometown postal history since I got interested in philately. I guess main reason is my general interest in history and history of my hometown.
I live in small town, Otepää. First post office opened here in 1895 but prephilatelic covers exist. At old times before it became town it was called Nuustaku and Nustago.
Those of you who collect German Occupation issues have probably heard of Otepää stamps, scarce and expensive mostly, printed in small quantities and used very briefly.
Besides seeking and studying material I have also started to actively research deeper background of local post. During the World War 2 most of the town was destroyed, burned down. Where were post office buildings before and shortly after war? What did they look like? These are questions not easily answered as it turned out. But it's fun to hunt for information and do a little detective work.
It turns out there are many ways to collect postal history. You can just collect items, you can study and research them deeper. But you can also try to find out about where post office has been in the past (if it's not public knowledge, written in the books readily available), who were working there, when and why postmarks changed etc.
For example in 1992 when Estonian Post did no longer accept stamps of Soviet Union and there was not enough of new Estonian stamps interesting things started to happen. Even large post offices encountered periodical problems. Smaller offices had bigger problems more often. Because of this and for the lack of various provisional issues, such as lack of stationery with machine surcharges, payment in cash markings were used (written by hand). It appears during first four months Otepää post office had several occasions where they lacked any other type of payment notifications. Sometimes they received some provisionals, sometimes they had to mark payment by hand. Such covers commercially used are (and I dare use the word!) rare. I own one and have seen five more and know atleast 2-3 collectors have them in their collection but other than that noone seems to have any for sale or trade or in collection. Several other smaller post offices had to choose the same route.
More of this in the future, with some examples from my collection.