Xena: True, there are a few tournaments which, if one trains units extensively, offer sizable rewards (if one is in an active coalition), but, at least from my experience, these are few and far between, not only regarding the tourney schedule but also the time it takes to retrain lost troops.
What sometimes disagrees with me, are statements claiming that tourneys are optional in this game, rather like "nice-to-have" perks.
A player at the mid-70ies level (such as myself) has completed most if not all building upgrades up those levels requiring sketches, therefore he or she will need to play tournaments to secure sketches, or win drachmas to buy sketches, which again means playing tourneys. There is no alternative, the odd drachma one might pick up here and there through achievements and the like don't account for much.
Please do the math: on a good week I will train 2m to 2.5m of troop strength which I invest in 1 tourney on the weekend (or two smaller ones, depending on the offered rewards). Training units for two weeks and throwing them all at one large tournament every fortnight is an option but doesn't really change the math.
Around 2.5m troop strength (and I'm being generous here) invested weekly, will get you perhaps 200 to 300 drachmas (and perhaps a sketch or two if a Dev Race tourney is on). A building upgrade from level 20 to 21 will cost around 120 sketches, therefore it will take 4 weeks to earn sufficient drachmas to buy sketches at the 10:1 rate (and again, I'm being very generous since that rate only applies if one buys the 10.000 drachmas = 1.000 sketches package, which is a VERY long wait). But let us again err on the side of caution and say it takes not 4 but only 2 weeks to earn sufficient drachmas (or sketches) for one level 21 building upgrade.
With around 25 buildings needing upgrades (17 production, plus harbor, port acropolis, infirmary, and so on), that's around 50 weeks of tourneys for all upgrades from level 20 to 21. A year.
Obviously it makes sense to concentrate on production buildings (and upgrade unit training times in academy and amphitheatre in order to increase training and unit strengths), but those savings won't amount to more than the 50% I've already reduced previously, not nearly.
But now look at levels 22 to 25 of most buildings: sketch demands usually more or less double with each level, therefore if it took me 50 weeks to upgrade all building to level 21, it will take me 100 weeks for the level 22 upgrade, 200 weeks for level 23 … and so on.
We are now no longer measuring upgrade speeds in years but in decades!
I sure hope Plarium is committed to this game since it has generational aspects. Will you still be running and supporting this game in the year 2030 when I'll leave my login to my son? :-) You better!
PS: And we haven't even discussed the fact that high-level agreements also require sketches.