You only need to live within the limits of your service plan, other than that, there are no imposed limits on the number of databases, number of queries or types of dashboards you can make.
InfluxDB can handle a lot of data, hundreds of thousands of writes per second, hundreds of queries, however this service doesn't cater to that level. This is geared towards infrequent sensor measurements coming in from a fleet of IoT devices.
The three main things to consider are database size, CPU cycles, and RAM use.
- Database size is fairly easy to estimate, everything in a write, in bytes, plus a bit for the database divided by the size of your Service Plan. Even with the smaller plan, you can get millions of entries.
- CPU cycles are harder to guess. It depends on how many reads and writes you are doing in what frame of time, the length of the data, and anything else the processor might need to do. If you end up using too much, your service will be throttled for a time.
- RAM use is dependent on the numbers of writes and queries per second, among other things. Using too much will cause out-of-memory errors.
You can move between plans and arrange something custom.