is it worth to update from ios mojave to a newer ios?

The Age of this computer will Govern what newer version of macOS it will Qualify to install. Use About this Mac from the Apple Icon on Desktop - the required Information will be there.

With the above information in-hand - follow this How to get old versions of macOS and verify what version this computer Qualifies to install.  For Best results use Safari to commence the download as Others may not work.

Safari will open a redirect and open the Apple Store where the download can commence.

Does this computer appear as Listed and qualifying for an upGrade to a newer version of macOS? 

The below links will help identify which version of macOS  this computer may Qualify to run.

Computer Qualifying for macOS 13 Ventura 

Computer Qualify for the Monterey upgrade

macOS Big Sur 11 hardware requirements

macOS Catalina 10.15 hardware requirements

Make Time Machine Backup  is very useful 

Does the user have a Full Rescue Plan in place and kept up to date ?

This would comprise having 3 Backups using 2 different methods and 1 Backup Off Site incase of Natural or Un-Natural Disasters ( like Safety Deposit Box of Bank )

Notation - Mojave is the Last version to support 32 bit applications / extensions and Drivers. Catalina, Big Sur, Monterey, Ventura supports only 64 bit and there is no workaround.

Suggest using Go64 to find 32 bit application before attempting the upGrade. Some or many of the Application already installed may require an update or upGrades to 64 Bit Version

macOS Ventura is full of amazing features and improvements, including Stage Manager, Continuity Camera, Freeform and more. A new macOS version often gets people excited about all the new features, but some may be on the fence about upgrading for fear of different software or lack of functionality. I would suggest you to update to newer version since mojave is a older version but its still cool. There is alot of new stuff in Ventura that you should try.

Just to add to playboicartii's fine info... there are drawbacks also, to start with...

Caution on 10.15 or higher, to see which Apps will no longer work in 10.15 get Go64...

https://www.stclairsoft.com/Go64/

Having a new OS can be nice however Mojave was probably the best OS Apple has issued (in my opinion). The newest OS (Ventura) has changed all the preference panes so you will have to get use to that and also removed the energy saver pane for auto shut down and start up if that is something you use (must use terminal script now). TM no longer backs up emails like before (that started with Catalina) so now more difficult to get a lost email.

Be aware that a few new features introduced starting with macOS Monterey are not supported on Intel Macs. However, this does not stop the OS from performing on Intel Macs.

I don't like that, so far I'm satisfied.

+1👍