Lol I can't believe anyone would keep Lydia as an active follower long enough to outfit her with fancy armor. I'd forgotten what a PITA she is until I restarted with a new character.
Lydia: "I've got your back."
Me: "Yes, very commendable. Unfortunately my front is wedged into this tiny space where the <insert highly desirable or necessary item here> was hidden. There is nowhere for me to go but 'back,' so can I have my 'back' back, please?"
Lydia: "Huh?"
Me:
*jostle bump jostle jostle nudge bump jostle bump*
Lydia: "OW!"
Me: *sigh*
She wasn't a bad fighter but she didn't seem very bright. She was always getting in my way, especially after I'd leveled up a bit and could take on more opponents on my own. I think maybe she was intended to be a "starter follower" who would take care of some of the lower level combat stuff in the earlier, "gimme" quests in the Riverwood/Whiterun area, but IME she soon becomes more of a liability in some ways.
I put soul trap enchantment on my bow as soon as possible so I could go out and hunt and 1) get pelts and hides for leather to help with my smithing and 2) get some cheaper soul gems filled up to use for enchanting and recharging stuff and 3) get some archery/sneak practice and use up some of the cheap throw-away arrows that I keep accumulating. I didn't dare *not* take Lydia along, because I never knew what I might run into and I didn't want to be caught in a melee alone.
However every time I shot an arrow at an animal that didn't die immediately, she'd treat it like an enemy that was attacking me and start chasing it all over the place and firing more arrows at it. So, you know, I've wounded a huge elk down to about half health with the first arrow, but I can't stalk it and finish it off because Lydia is now chasing it across the tundra screaming and shooting at it. Even if I tried to follow her in case she killed it and I could still get some supplies from it, it still didn't pan out as she never seemed to succeed in actually finishing off anything I'd hit. She'd just scare it so far away that I couldn't finish it myself.
She would continue chasing whatever poor critter I'd shot at as long as I had my bow drawn and didn't move away from the vicinity. She'd chase something from Whiterun to Rorikstead and back if I let her.
Perhaps I should've taken a wild shot at a distant mammoth just to watch the ensuing hijinks.
Anyway I made her a steel helmet and made sure she had as good a bow/sword/shield as I could manage at the time, and that was it. Kept her around long enough to grab enough swag to buy and fully furnish the house in Breezehome, where she now resides in perpetuity or until I get very, very poor and desperate for some help.
Went to Riften as a little side excursion and hired Marcurio and sent Lydia home. What was cool was that when my new follower and I left Riften on our way to my next adventure, we actually passed Lydia on the road back to Whiterun hold.
At my current character's level(s) - working my way up through the 20s - having a mage as a follower is awesome. He gets and actually makes good use of any staff I find and want to give him, which I don't do as well since I concentrate on two-handed weapons and if I've got a smaller one in my right hand it's because I want a shield or maybe the flame spell for draugr immolation in the other. And it's so much fun to watch him battle another magic user. He's also more of (and a much better) conversationalist than Lydia, altho that's not really an astounding achievement.
I've now got him fitted out with Elven armor, all enchanted to boost his Magicka and/or Stamina and/or Destruction skills as is all the jewelry I've given him. I may throw some Resist Frost bling in there if he doesn't stop complaining about the Skyrim climate.
I gave him up with my last character so I could travel with Vilkas as follower/spouse but I don't know if I can let him go this time. He's my own little Imperial Magigolo.
BTW for those of you playing out of Breezehome, there is a mod that will put an enchanting table in with your alchemy set. You have to buy the alchemy furnishings first and then enable the mod. It removes the small table and chair to the right of the alchemy table, and puts one wider table in there with the alchemy set on the left and an arcane enchanter on the right. Saves all that running back and forth to Dragonsreach to use Farengal's enchanter.
The only thing I don't like about Breezehome (with the arcane enchanter mod working) is how small it is, which means there is way less storage space. It also gets very crowded if you have Lydia there as housecarl plus another follower hanging out on the premises. Heaven forbid you should marry a third person and have him/her move in there.
What I've heard/read is that the house in Solitude is not worth the price even when you get it furnished - but the house in Windhelm, when cleaned up and fully furnished, is by far the best property, with just about every possible convenience available for purchase once you buy the house. Windhelm also has a blacksmith with all the available workspaces and a smelter on site, and he generally has enough money to take stuff off your hands if you're picking up or forging a lot of weapons and armor. There is a good market area near the blacksmith for more bartering in weapons and armor, general merchandise, food, and alchemical supplies. For some things you may still want to hit up the wizard in the palace, but that shouldn't happen too often.
BUT - you can't have the house in Windhelm without getting involved in the civil war, because it doesn't become available until that storyline is either fully or partially resolved depending on which side you take and nothing happens with that storyline unless you get involved in it.
I wonder how my Imperial Magigolo will feel when his Skyrim Sugar Mama joins the Stormcloaks?