Looking to purchase a garmin watch but not too sure what one? I run a lot. Do spin classes. And go the gym. Any suggestions?

I have the forerunner 735xt. Fantastic watch for tracking a lot of activities, but it won’t track spin class at the gym, if you are planning a triathlon, you will need to add speed/cadence sensors to your road bike and the watch will then track that for you. You can download a strength app to use on the watch to track any weights sessions you do at the gym. Hope this helps a little.

Great watch for running, I have it and still love it. If you don't care about stairs or accurate elevation doubt no longer and go for the 735. :)

For spinning you could use the indoor cycling builtin profile or use a connect iq app like this https://apps.garmin.com/en-US/apps/722b39e9-ba24-40e0-97f3-23faf2a61885 (haven't used this so not sure if and how it works)

GArmin fenix-6 solar has everything you would ever require, including solar powered !! you can do pretty much anything with it. yesterday i ran indoor track , swam 1- km in a pool and done a light workout in the gym. all recorded on Garmin with the touch of a button . it told me what my time was for each 25 meter split in the pool and overall heartrate with time per 100 meters very impressive watch 

I loved my old 645/Music except it didn't have "Open Water Swimming" so I upgraded to the triathlon-focused Forerunner 745. This 745 does everything my old 645/Music did and has Open Water Swim. If you don't care too much about open water swimming you can probably pick up a 645/Music for a song. Super cheap. Try it out, and I'll bet it'll do everything you need.

I'd skip the 735.if you don't care about music or maps on the watch, you can get the Fenix 6 for $300 from bike closet. Just did that as my 735xt just went wonky after swimming with it all week. About $150 cheaper than the 745 (735's replacement). The newer watches have much better HR and wellness related tracking/info. So if I was starting from scratch, I wouldn't touch the older watches at this point. I also had no faith of getting advanced sleep info on the 735xt. Just a few months away from being a few months away, blah blah. But for $300, I think the basic Fenix 6 is a steal. I get my music from a shanling m0 I clip on my hat and can go BT or wired for headphones, and I don't care about maps which is essentially what you pay 150 more for the 745. You can still pick up old Sansa Clips for music and clip them anywhere with wired buds. 

For spinning classes, depending on the bikes they have, there are some nice apps that can track a lot of info, and you can put your watch into HR broadcast mode. I have a Precor Spin power bike, and my gym uses them as well. I use this app that gives me all my info. Helps the bike has real power so I can track my wattage with mileage and HR.

https://play.google.com/store/apps/details?id=dev.csaba.track_my_indoor_exercise

It needs a few things, but it is the most complete. Keyser has an app for their bikes as does Stages. The app above works with a few different bikes as long as they support BLE.

Wahoo stopped ant+ support which is what I used to use. Then Samsung ditched ant+ support. Planned obsolescence so they can sell you new BT devices just like losing the headphone jack. Annoying as f**K. Wahoo does BLE and is nice, but you don't get power. Also annoying. It's just data and fields. In 2022, these companies need to get over the proprietary crap and let these apps map their fields so we can easily utilize the data as we see fit. 

Here's my spin class this morning. Slacking a little as I practiced my pump class beforehand and with two leg tracks, I was wiped. It'd be nice to have the average metric during the workout, but it's not there yet. Hopefully gets added soon. Have to drop them an email. So much wasted space and overly large fonts for something that's less than 2ft from your face on the bike. 

I'd skip the 735XT.  It is a great watch and I have loved mine, but it is outdated.  I would check some of the newer Garmin models.