Lens maintenance help needed

[LaserTam]

Not used my SLR much in the last few years, lacked inspiration and time to be honest. But I did use it the other day and noticed an issue. Its a Sony A100 and using a Sigma lens - noticed that when zooming in and out it didnt feel very smooth, juddered slightly if that makes sense. It didnt sound or feel like there was anything in the mechanism to cause this, but perhaps just a bit stiff from under use.
Wondering if there are any tips people can offer to try and resolve?
TIA

[Craikeybaby]

Send it to Sigma for a service?

[LaserTam]

well yes I could, but like I said, extremely under used so hard to justify. Was hoping some bright spark would give me a top tip to ease the mechanism.

[Simpo Two]

Well...

a) Have a go yourself but possibly make it worse/not be able to put it back together. How expensive is the lens and how lucky do you feel?

b) Send it to a professional plus money.

a) Use it as is.