Well, standard operation for take off and SID's is of course LNAV/VNAV, LNAV is active from 50ft on and VNAV from roughly 400ft AGL.
Arrivals is a different matter. Usually we will get vectors at some point and from that point on VNAV becomes more of a nuisance than a help, basic modes work much better. But even if you get a clearance for a STAR and approach very far out and could fly in theory LNAV/VNAV until GS intercept it works better if you take VNAV out within the last few miles and use basic modes.
I tried it several times, even with all information filled in it will decelerate way too early, early enough to be fully configured at the FAF. In real life that is detrimental to traffic flow and actually not SOP nor recommended practice.
VNAV works fine during large parts of the descent, but within the TMA or latest during the last 10 NM prior FAF i prefer not to use it. Level change works well, but can induce too high descent rates when close to terrain, V/S is in many cases even better. A good pilot uses all tools available, which means of course all auto flight modes, and if he wants to, no auto flight modes at all.
I have to say i can't really measure up to many of the high post count guys here. Although i started flying at age 14 (earliest legal age back then in germany) it took me quite a while to start flying professionally, only do it for the last 11 years, and only on 737s. First the 300 and 500, since a few years back the 700 and 800. Due to my "other job" my flying is nowadays limited, i manage around 400 hours a year. In my opinion tech log is probably the most interesting part of PPRuNe with a pretty high density of professional posters, but as genghis mentioned many of them are not pilots, which is actually the interesting part since we pilots do get quite a few inputs from those professionals that usually know a lot more about certain parts of aircraft, flying and procedures. And of course many of us pilots do work in additional capacities within our airlines, be it training, performance or technical.