Road Bike shifters

My road bike is a 2007 and my shifters that came on it are the originals. For some odd reason they have been starting to seize on me lately. It's not to the point I can't use them but they are getting hard to push at times and feel like it takes more effort to get the gear started to shift than it did. My cables are newer and I've had mechanics look at it and they never can tell anything is wrong. It makes me wonder if they are just simply starting to wear out? I suppose they probably have around 6-7,000 on it? I've changed computers several times so I am not sure exactly. I have the updated 105 road shifters on my commuter which is newer and I have to say I adore that new design after riding on my old shifters today. The new ones have that flat spot on them and it fits my hand a LOT better. I don't feel my neck muscles getting tensed up as much with the new design. The shifting is so much smoother too.

So should I think about buying some new shifters for my road bike at this point? I would definitely want Ultegra since most of my other equipment on the bike is Ultegra.

Thoughts?

What kind of shifters are they?

They are Shimano ST700 STI, "Flight Deck". Originally were for triples but I converted to a compact.

if you aren't ready to toss them just yet, try soaking them in some solvent. The Bike Hermit just had to do that on a customer's pair as the gunk and grease was causing them to not work at all. Now they are fine.

What I did with my R700s was flush them with solvent (WD-40), which I could do without taking them off the bike - just roll back the hoods, put a catch bottle, drip tray and towels underneath, set your sprayer to "stream," and pump WD into the mechanism and let it stream out.

But, the symptom I was having - which people here told me the solvent flush was a potential fix - was that the ratchet wouldn't catch, not that it was hard to push. I would push and the lever would move but nothing would happen with the cable. So not the same symptom as yours. Still, couldn't hurt to try.