I realized what I wrote earlier (since deleted) may a little confusing. I'll try to make it a little more clear.
The 375 has 5 pieces of information:
1. Navigation (updated every 28 days, $299/yr for USA)
2. Basemap (updated randomly, $100/yr)
3. Terrain (updated randomly, $150/yr)
4. Obstacles (updated every 56 days, $195/yr)
5. SafeTaxi (updated every 56 days, $215/yr)
You can buy a la carte and spend $959/yr ($299+$100+$150+$195+$215) or you can buy their bundle and pay $499/yr. However if you want to take the trouble to evaluate your needs every few months, you can look at it this way:
#1 (Navigation) is mostly used for IFR so if you're going through instrument training then you'll need this. It also has airspace that may be of use for VFR but how often does that change?
#2 (Basemap) is mostly used for VFR but it's updated only every 1-3 years. You can simply buy a 1-time update for $100 whenever that happens rather than paying an annual subscription for something that doesn't change annually.
#3 (Terrain) is mostly used for staying out of the rocks. You can simply buy a 1-time update for $150 whenever rocks move. According to Garmin, the last time this happened was in 2016.
#4 (Obstacles) is mostly used for staying out of antennas and skyscrapers. You can simply opt not to fly near them or buy a 1-time update for $50 whenever antennas and skyscrapers move. According to Garmin, this happens every 56 days.
#5 (SafeTaxi) isn't that great on a 2inch high screen. My personal opinion is that a tablet does a better job at this. Or you can ask for a progressive if at a towered airport. Or you can hope that the airport layout hasn't changed since the last time you bought an update.
... So out of #1 through #5, you can probably get away with only subscribing to #1 for $300/year and do #2-#5 on an as-needed basis.