OBB tickets

Its waaay too soon. Start looking around 180 days out. Some trains may only be available later, depending on schedule updates. Trains run around 2 per hour and there's really no need to book far in advance. DB Regional trains (BRB or RE) can't be seat reserved but may have the cheapest prices, with the option of using a Bayern ticket for up to 5 people.

You have a few options. None require you buy tickets now. You can even safely buy your ticket on the day itself. This is mass transit.

https://www.seat61.com/trains-and-routes/munich-to-salzburg-by-train.htm

Why not just take the hourly regional train from Munich to Salzburg. You don't have to buy until day of travel, and a Bayern ticket makes it cheap after 9 am, even cheaper with more than one.

I easily get confused and forgetful. Because of this, I try to arrange everything as soon as possible and then write it in that trip's itinerary so I don't forget. Had I received a date the tickets were available, I would have entered it on my calendar.

I do not do well with impromptu changes, so having preselected seats helps with confusion.

I'm a hot mess, but I'm not going to give up.

Do you also buy subway tickets months in advance?

Trains are mass transit. It is not necessary to worry about them months in advance. Most train tickets are still sold on the day of travel itself.

Trying to buy tickets for Munich to Salzburg for 4 Dec, 26. The OBB web site shows "tickets not available".

Salzburg is technichally both an Austrian and a German station. So technically, you'll be taking a trip within Germany, which you can book through Deutsche Bahn (https://int.bahn.de/en?dbkanal_007=sprachauswahl-en)

Of course, it is just public transportation, but it’s hard for me to think of a ticket that costs over $75 for a ride that takes nearly 2 hours in the same way as a 6-block bus ride. While it may be too early to buy for December it does not hurt to keep in mind that the cheapest ticket available will vary with when you purchase it. You are buying 4 tickets? You can save $150 if you can live with the rules. Here is an example:

Munich to Salzburg 20 March (tomorrow) 10:16 – 11:59
OBB 56.80 € each
DB 30.49 € each
Munich to Salzburg 3 June (several weeks in advance) 10:16 – 11:59
OBB 56.89 € each
DB 25.49 € each

Rules
OBB 2nd class including seat reservation.
Cancellation free of charge until the day prior to travel.
Valid day of ticket and the following day
Free choice of the means of transport.

DB 2nd class including seat reservation.
Train-specific travel
No cancellations
No City-Ticket

But the Bayern ticket, referenced above, on the slightly slower regional trains costs a total of 74 Euro for 5 people, can be purchased day of (or up to 6 months ahead) and is valid on any regional train

Isn31c that's useful!!! Live and learn. http://www.munich-touristinfo.de/Bavaria-Ticket.htm