Which earlier generation of phones do you use/recommend?
Longer answer depends of what features you need: j2me (for reading HN if needed), qwerty keyboard (for writing long comments on same resource), jack 3.5mm (for radio/mp3/lossless depends of smartness), quality of camera if any, longevity of body, maybe something unique like that feeling from opening/closing a 8800. Somebody cares about GSM-900 which works best in deep woods. Today before buying smartphone we are reading about how much RAM and pixels it has and that's all. But 15-20 years ago choosing a phone was really interesting process.
Consider having several chargers especially if you are going to use something not common and not famous by longevity like thin Nokia's port. Maybe you want to solder USB-A instead of a socket with an integrated power supply to your proprietary charger socket (if 5V) to let your dumbphone be charged from powerbanks, for my Nokias with thin charger it works perfect. Avoid sh~ like Sony Ericson's FastPort (which is required for charging) and rare memory like MMC and prefer MicroUSB for charging and MicroSD for storage. For example, I love listening podcasts so my memory cards doesn't live for a long time if every week I need to refill all the memory with new files - but MicroSD costs next to nothing. Consider having extra batteries or maybe several phones having similar battery, especially if you love hiking. For example, some old Samsungs can use battery from smaller Samsungs (with spacer made from anything) and Nokia's BL-5C is one of the most popular batteries ever.
Nokia 1280 has jack 3.5 for a radio, a lighter (poor but better than nothing), its body is not much weaker from 3310 but replaceble without a screwdriver with several colors from grey to purple. Battery is not BL-5C but its SIM slot works decent even with cut simcards. So let this dumbphone be my go-to answer.