Aside from the battery, upgrading from HDD to SDD gives a new leason on life to older Macs.

I was about to throw away a 2008 or 2009 (?) MBP as totally useless, but instead I threw 100 bucks or so at it - superdrive came out into an external casing, the HDD went to its place as a large(ish) capacity data drive and a brand new 128GB SDD went in as primary drive. In the process it was "hoovered"from the amazing amount of dust that collected inside and the heat pastes were also renewed.

It was like magic afterwards - a fast, modern machine instead of the old clanker. Obviously the CPU remained the same (so no heavy video editing - but I don't do that anyway) and didn't upgrade the RAM either, but again, even if it's swapping (hardly ever) it swaps to the fast SDD.

With this done, the need to lug the main laptop to the holiday home also went away.