If its advisable to have both upper and lower eyelid lift together?

Common. If you do not have dry eyes then both upper and lower lids can be treated with surgery at the same time.
Not a problem. Upper & lower eyelid lift (blepharoplasty) is very commonly done together. Dry eyes is not a contraindication for 4-lid blepharoplasty, provided the surgeon is not too aggresive with the skin excision. With a balanced and measured approach, your surgeon should be able to achieve a more youthful appearance for you with a lower risk for complications.
It can be. Having both upper and lower eyelids done together can save you from additional anesthesia, recovery time and discomfort. It adds additional swelling, but not a dramatic amount. It can also save you money as many doctors discount the lower eyelids when performed with the uppers. From a safety standpoint, in good hands there is no difference.
If needed, yes. In the upper lids, the problem is usually too much skin. In the lower lids, the problem is usually too much prominent fat. If there are problems in both areas, these procedures can easily be combined, but they do not have to be. It depends on what the anatomy is and, more importantly, what bothers the patient the most.
DEPENDS. Upper and lower eyelid lift surgery is frequently performed at the same operative session. Other procedures such as brow lift, facelift, fat grafting, laser skin resurfacing may also be done at this time.
Generally okay. An experience board-certified surgeon can determine whether or not is okay to have the upper and lower eyelids done at the same time. That being said, it is a common combination and can be performed safely in the right hands.

Related Questions

What're the problems surrounding a lower eyelid lift?

Minimal. Usually there are no problems with lower lid blepharoplsty, but every operation has risks and complications. Your surgeon should discuss these prior to the procedure. Read more...
Generally Safe. Main concerns relate to under-correction (not enough fat/skin removed or muscle not tightened adequately) or over-correction (too much fat/skin removed). The result may be less improvement than desired with under-correction versus hollowing, rounding or a pulled-down appearance with over-correction. Much more serious problems such as muscle injury or vision loss are very rare, fortunately. Read more...
Usually minimal. If you do not have dry eyes lower eyelid lift is usually minimally painful or irritating. The eyelid can swell and bruise. The eye will get temporarily dry, and near vision will be a little off for days to weeks. If the eyelid tension is weak the lower lid may pull down while it is healing. Your doctor may suggest more extensive eyelid lift if he or she notes that condition preoperatively. Read more...
Lid sag. Lower eyelid lift is technically more difficult and much less forgiving of surgical error than upper eyelid lift. Because gravity is pulling down on the lid, it is very easy to cause lid sag after lower eyelid lift, especially in patients older than 55. If the surgeon is experienced and cautious, the procedure can be done safely. Read more...
Lower blepharoplasty. Lower lid blepharoplasty is a very safe procedure in experienced hands. Your best bet would be to have your eyes evaluated by a board certified facial plastic surgeon. Read more...