The biggest issue is to avoid injuring yourself by having high pressure oil injected into your body.
It is human nature to hold your hand over a suspected leak. In a hydraulic system, the jet of escaping fluid can be so small that it would take a magnifying glass to see it.
Most newer Kubota Owner's manuals contain the following caution.
In terms of what to do when a leak happens, this depends greatly on the hydraulic circuit being served. A hose serving a FEL bucket is not serious and will not leak any more if you do not send any flow to the bucket. You can safely drive back to a place to repair it.
In general terms, replacing all hoses before they break will allow you to do the replacement at a convenient time.
Hoses bought from a local shop who fabricates the hose and its ends or hoses bought on line will be more economical than ordering Kubota parts.
Dave