Sluggish Internet connection

I find that my DSL Internet connection at home get sluggish as the day progresses. I reboot my modem-router combo weekly, which helps initially, but gets worse over the next week or so.

I'm wondering whether I need a new router-modem. I've had my current and only one since I became a customer with my Internet service provider eight years ago. Maybe a technology update would be helpful.

I'm not sure whether upgrading my Internet service plan would be worth it. Anyway, I've asked support to look into my sluggish connection and see what suggestions I get.