Hi,
There is no specific number of new firmware that will be released in a year. It's based on the stability of the previous version and also depends on the new function’s achievement plan.
If you want to see the official release software or patch version, you can check from the Huawei support website.
Using the S5720-52X-PWR-SI-AC switch as an example:

https://support.huawei.com/enterprise/en/switches/s5720-52x-pwr-si-ac-pid-22347192/software?offeringId=6691579
The upgrade is not necessary when the device is running stably. However, it is recommended that you periodically upgrade your device to the official recommended version.
Hope the provided information is helpful for you.