How many does it take to change a light bulb ?

I have no experience with Internationals but from what I recall they are similar to the Mack I had. If in fact that is correct then you can change the bulbs or upgrade to an LED assembly yourself as I did on my Mack.

 

Are they Led or halogen?
Led is most likely a sealed unit.

 

Call the dealer, give them the VIN they will tell you, ask for parts number, google parts number, order what you need, watch YouTube how to, install, be happy!

 

Is the plastic hazing? Some of those kits work for a while.

 

Sylvania Home (sylvania-automotive.com)
On the website you can select your vehicle and see what headlights are available. The brighter the bulb the shorter the life. And don't touch the actual bulb, best to wear latex gloves. Oil from your skin will cause the bulb to burn out very quickly. Lights do get dimmer over time. I would also check and clean any grounds for the headlights, probably along the frame rail next to the engine. Follow the harness from the headlight.
Walmart sells a lot of bulbs at excellent prices in the automotive section if your truck has that type.
HOW TO CHANGE YOUR HEADLIGHTS ON A INTERNATIONAL PRO-STAR - Bing video

 

you can try adding a direct 12 volts to the bulb to see if it brightens up. or do a voltage drop. 2019 RH led assembly is probly over $1k each. you can add driving lights for way cheaper. i use aluminum polish on my old lights.