Reddit mentions of Timetec Hynix IC Apple 16GB Kit (2x8GB) DDR3 PC3-8500 1066MHz Memory Upgrade for MacBook 13-inch Mid 2010, MacBook Pro 13-inch Mid 2010, iMac 27-inch Late 2009, Mac Mini Mid 2010 (16GB KIT)

Well, first off: OS X 10.11 El Capitan isn't the newest macOS version for your MacBook Pro. Your MacBook pro actually supports macOS 10.13 High Sierra. High Sierra can still be downloaded from the Mac App Store, it is just hidden. Here is the link to it (click this link in Safari only, not in Chrome or Firefox!):

• https://itunes.apple.com/de/app/macos-high-sierra/id1246284741?ls=1&mt=12
  
  OS X El Capitan went out of support in the fall of 2018, so it has been missing out on security for quite some time. Every major macOS version has 1 year of mainstream support (the time frame between its own initial release and the initial release of its successor one year later) and two years of security support immediately after that. Security support includes Safari updates.
  
  Mainstream support for High Sierra has already ended, but its security support only ends in the fall of 2020. So if you update your MacBook Pro to High Sierra, it is still safe to use.
  
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  You can speed your machine up by adding more RAM and an SSD to it:
  
  Your MacBook Pro supports up to 16 GB RAM (2 x 8 GB RAM modules). A higher amount than that won't work due to a limitation in the logic board.
  
  You need to buy RAM that matches the following specifications:
  
  PC3-8500 1066 MHz DDR3, 204-pin
  
  Those are some examples of RAM that should work:
  
  
• https://www.amazon.com/OWC-PC8500-SO-DIMM-MacBook-OWC8566DDR3S16P/dp/B00BKVQFCU
  
• https://www.amazon.com/dp/B00KFNBP24/ref=twister_B07FSYCMM9?_encoding=UTF8&psc=1
  
• https://www.amazon.com/Mushkin-997019-204-pin-DDR3-1066Mhz-PC3-8500/dp/B006E0P1IG
  
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  As for the SSD, your MacBook Pro supports every SSD that meets the following criteria:
  
  
• 2.5" form factor
  
• SATA3-compatible
  
  Here are some examples of SSDs that should work:
  
  
• https://www.amazon.com/Samsung-500GB-Internal-MZ-76E500B-AM/dp/B0781Z7Y3S
  
• https://www.amazon.com/SanDisk-500GB-Ultra-NAND-SATA/dp/B072R78B6Q
  
• https://www.amazon.com/Blue-NAND-500GB-SSD-WDS500G2B0A/dp/B073SBZ8YH
  
  Before you install the SSD, it is advisable to create a backup of the files you want to keep. Store them on some external drive.
  
  You can then reinstall macOS either via Internet Recovery or a macOS 10.13 High Sierra installer USB-Stick (which is the last OS your MacBook Pro supports).
  
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  As for the battery: The battery is replaceable in MacBook Pros 2010. However, you won't be able to get an OEM battery Apple uses, most likely. Those are sold out by now and no longer available, unless you are extremely lucky. There are third party batteries that work, though, like this one for the 13" version(!):
  
  
• https://www.amazon.com/HUSAN-Compatible-661-5229-661-5557-020-6547/dp/B071G53YBQ
  
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  > I also heard mixed things about the new butterfly keyboards, but overall it seems once you get used to them they make your typing faster? So that sounds good for me if it's true
  
  The problem is less the feeling of the butterfly keyboard; beauty is in the eye of the beholder. The problem is that the butterfly keys sometimes outright fail if small particles - like dust - intrude under them. I have discussed the problem here (last paragraph):
  
  
• https://www.reddit.com/r/mac/comments/b86zvo/macbook_retina_vs_macbook_air_school_me_on_which/ejwayit/

https://www.amazon.com/gp/product/B00KFNBP24/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

This is the exact ram that I put in my mid-2010 13" about 6 months ago and I haven't had any trouble so far. I'm not sure if its compatible with the 15" though.

My specs: https://imgur.com/a/FJNqral

Cost me about $150
I got these:



Kingston Digital A400 SSD 480GB... https://www.amazon.ca/dp/B01N0TQPQB?ref=ppx_pop_mob_ap_share

Timetec Hynix IC Apple Compatible... https://www.amazon.ca/dp/B00KFNBP24?ref=ppx_pop_mob_ap_share