I hope this is the right section to post in...

I'm looking at getting another handheld GPS , I used to have a 60csx years ago and worked well. I know I want topo maps and replaceable batteries.

So I guess it's between the 64 and 65 from Garmin.

I guess what I'm wondering is what's the difference between the 64 and the 65?

I don't mind buying used, so if I can save a bit by buying an older model , I'd do that.

Maybe just get another 60csx? I looked them up and I'm saving a little bit more but If the newer models lock better and hold signal longer - definitely worth it

I have a Montana, and it is nice.   However, since I moved to OnX,
The Montana is just not getting used.   If you have a decent smartphone look into it.   I was carrying both till I got confidence in OnX then quit carrying the Garmin.

Appreciate it. I want one for a durability aspect

This is my third Garmin.  By far the best, huge screen and seems pretty durable.   I use my phone since I always have it anyways to comm with my Inreach.  Montana something, kind of the mid price one a few years ago.

Does not look like too much diff between the 64 and 65 series.. Two more systems it can use..  QZSS and IRNSS and it looks like double the memory to 16gb.

My 60csx is getting long in the tooth too, so also kinda figuring out what I want next.  I do want a 6x series one though.

I will 2nd the guy above about using your smart phone.
Between the normal run time of the phone and a spare battery pack I can run it in GPS only mode for several days.
Get a decent case and it should be nearly as rugged as a regular GPS.

I use Gaia as my GPS app and have been very satisfied with it. I have downloadable/offline maps, uplink to the web (when online).
2 years ago I used it when up north in Canada on a remote fishing trip. When compared to my buddy's new Lowrance GPS/Fish finder, my phone was equally as accurate and had the benefit of utilizing satellite photos for navigation. We actually ended up using it almost exclusively when navigating up and down the rivers, the sat imagery showed the shallow spots and sand bars clearly.

If you are really concerned throw your old cell phone into your pack with the application installed as a spare (two is one and one is none).
My old iPhone 5 is not HSLD but it runs my GPS app just fine.

The big advantage I see to a dedicated GPS will be you have all the maps at your command, not having to download the area before leaving home.

As I said on your other post look at Garmin 78 series if your around water as they float.

Battery life, ruggedness and immersion. I also prefer gps units that have standard AAs, same as my pocket/headlamps..

If I'm out doing woods things, the phone gets shut down. The only time i might turn on the phone would be at rest breaks or camp.

Used several handhelds for the last 15 years. My favorites are the old Garmin 60csx (now retired) and my current fave,  an Etrex 20x.

I don't like  touch screens. The units mentioned have screens that work perfectly under direct, noon sun.

Everybody has their personal favorite equipment and I am not necessarily going to find fault in using a dedicated GPS, however:

-- I typically download the maps for the areas where I am going to be in as well as the surrounding areas. I have never had the occasion to venture off of the area of my downloaded maps. I would need to be something like 50 miles off course to get to that point.
-- Your touch screen comment is valid, however short of the GPSMAP series many of the GPS units today have a touch screen
-- Many of today's smart phones are water resistant and or better than the dedicated GPS offerings (The Garmin GPSMAP 64 is rated for immersion to 1m for 30 min. The current iPhone are rated for 6m for 30 min)
-- Phone chargers can be had that run on AA batteries.
-- The case on my current phone is at least as rugged as was my Garmin Etrex
-- Put in airplane mode my phone will run for 2-3 days on a single charge. In contrast a Garmin GPSMAP 64 will last 16 hours on a fresh set of batteries

You are certainly entitled to your preference, however the line between a dedicated GPS and a phone app is getting much less distinct.

True, but i prefer redundancy in outdoor equipment. Garmin makes a GPS that contains a mapping GPS and Inreach satellite texting guts. I carry a nice compass, an Etrex 20x, a Delorme Inreach and the phone has Backwoods Navigator with downloaded maps. I also carry a headlamp, a small pocket flashlight. Those and the Etrex all sip the same AA batteries. I don't trust things with batteries.

BTW, if I'm in the woods, all that stuff is turned off.  If travelling the most used item is the Etrex. Most of its use is to mark a place of interest or plot remaining distance. It goes off again right after. Might turn on the phone when resting at a high place. Inreach goes on a few minutes at camp to let my loved ones know I'm  OK.

In addition to the things already mentioned about dedicated GPS units.

Don't forget that most dedicated GPS unit have a significantly better antenna than the small patch antenna your phone has.  The patch antenna in your phone is about the size of your finger nail on you pinkie finger if not smaller. Garmin units are using a patch antenna with many times greater area, and many of the units like the GPSMAP 6x series use and even better quad helix antenna. This might be the difference between getting a lock or not under a heavy wet tree canopy or down in a slot canyon.

None of the phone GPS chipsets can use the WAAS system yet either.  Most Garmin GPS units are capable of using the WAAS system and this improves accuracy significantly.